** A64 Overclocking Guide **

[THunDA]

**IMPORTANT NOTE**

This overclocking guide has been merged with a few other stickies.. Its best for you to read "THE" Definitive DFI AMD Overclocking guide! instead of this one ...

 

 

 

 

 

 

I wrote this guide with the help of a freind of mine.. WildStyle from Guru3d.com .. I figured maybe it will help some of the peeps at DFI Street out too.. Its not a totally complete guide but it will sure help out some people just getting started..

 

Since there seems to be a large increase of people upgrading to a64 rigs WildStyle and I (THunDA) have decided to write up a little guide to help everyone overclocking their A64 rigs. (THunDA can take full credit for this.. hehe)

 

First we are gonna go over most of the basic settings that you will find in an A64 motherboard BIOS. It’s possible that different manufacturers might have things named differently, but they should be similar for the most part. If you are unsure of a setting then be sure to ask. After this we will explain how to find the max of each component separately which is the most important and overlooked part of overclocking.

 

 

FSB/HTT Bus Frequency

This is what most of us know as Front side bus ( FSB ) but now with a64’s it is called HyperTransport Bus Frequency ( HTT )..

Wildstyle says..

HTT effectively equals FSB, but in actual fact there is no FSB. Current CPUs (except the A64) use an FSB. This is a 64-bit or 128bit wide path transferring data between the CPU to the memory controller. The memory controller is housed in the NorthBridge on non A64 mobo's and data gets transferred between the mem controller and CPU via this 64bit/128bit "lane." 64bit is single channel, and 128bit is dual channel.. where an extra "lane" is opened, but that's another topic.

 

The A64's memory controller is built into the CPU itself - it is on-die. The benefit of this on-die memory controller is that the data no longer needs to visit the NorthBridge. This reduces latency and access time, and so on an Athlon 64 the data can be transferred without wait. That is essentially why the A64 is faster.

 

The A64's architecture depends on clock speed to make use of memory bandwidth. The higher HTT scales with clock speed, but does next to nothing on its own.

 

LDT/FSB Frequency Ratio

LDT is just like your CPU multiplier but it’s the multiplier that makes up your total HTT speed. Here is something I’ll quote from Wild that shows how to get your total HTT frequency..

Wildstyle says.. HTT is your “FSB.” LDT is the HTT Multiplier (LDT = Lightning Data Transport)

 

So for example on your system we could use..

 

200 (HTT) * 5 (LDT) = 1000 (HyperTransport freq.)

 

HTT * LDT = HyperTransport Bus Frequency.

**Important note**

When overclocking you want to lower this setting to maintain stability. On a socket 754 its best to keep your total HTT speed around 1600htt or less, as Wild explains above this will not effect performance if running under spec a little.. On socket 939 its best to keep it around 2000htt.. Sometimes on 939 you can even get away with overclocking the HTT buss a little but honestly Ive never seen a performance boost by doing this..

 

CPU/FSB Frequency Ratio

This is your CPU multiplier.. This times your HTTFSB is how you get your CPU frequency..

 

**Important note**

On all a64 systems it is not recommended to use half multipliers ( i.e. 8.5,9.5,10.5) because this will put your ram on a ratio which means it will be running slower then you think and not the same as you have your HTTFSB set to no matter what..

 

A quote here from Wild shows what happens to your ram speed when using half multis…

Wildstyle says.. (DRAM frequency) X (RAM divider) = CPU frequency

 

Dividers are all whole numbers, so if you use a half multiplier your memory speed is calculated by using the next highest whole number.

 

An example...

 

200X10 = 200/10 (divider) = 200MHz

 

200x10.5 = 2100/11 (next highest divider) = 190MHz (effective memory frequency.)

CPU VID StartUp Value

This is the voltage that is applied to your cpu before the Vid and special are applied during post.. I havent found this to be a very important setting but normally I just leave it at 1.5v .. I also ran this using the Startup setting and it didnt seem to effect anything in a bad or good way.. So from my personal experience its not really a vital setting..

 

CPU VID Control

This is your vcore which is your CPU’s voltage setting ..

 

CPU VID Special Control

This may be named different depending on the motherboard but it normally has options that look like this..

 

104%, 110%, 113%, 123%, 126%, 133%, 136%

 

What this does is let you add more vcore to your CPU when your regular vcore options are not enough.. What you do is multiply your CPU VID Control with your CPU VID Special Control to get your actual vcore. Here is an example of using the VID Special..

 

CPU VID Control = 1.50

CPU VID Special = 110%

 

1.50 x 110% = 1.65v

So with this setting your giving your CPU 1.65 vcore.

 

And for you lazy people..

This says its for the DFI 250gb mobo but it will work for any mobo that lets you add % to the vcore..

 

Chipset Voltage Control

This is the voltage applied to your motherboard chipset. The stock voltage for my chipset is 1.5v, but currently I’m running mine at 1.7v just to make sure its getting enough juice since it runs pretty cool for me anyway. I haven’t noticed much of an improvement in stability with upping this voltage as I did when I had a nforce2 motherboard but I like to up it a little anyways.

[THunDA]

AGP Voltage Control

This is the voltage applied to your AGP slot... Sometimes upping this will help a little with stability in 3d benchmarks or games when you’re overclocking a lot. Some of you with PCI-E boards like my self will not see this as an option in bios.

 

AGP Frequency PCI-E Frequency

This is the bus frequency of your AGPPCI-E slot. You wanna treat this very much like AGP voltage because it doesn’t really help a lot with stability, but sometimes it may help a little to bump it up a FEW MHz.

 

Dram Voltage Control or Vdimm

This is your RAM voltage. Setting this will vary a lot depending on what type of ram you use and more importantly what IC’s are on your ram sticks. Some ram will like a lot and then there is some ram that will be less stable with too much.

 

For more info on RAM, check this thread out:

http://forums.guru3d.com/showthread.php?s=&threadid=95128

 

K8 Cool 'n' Quiet Support

This option, when enabled automatically lowers your vcore and CPU multiplier when the system is idle. It’s highly recommended to disable this setting when overclocking.

 

FSB Frequency Ratio

 

This is your Dram ratio option. This is another one that might be listed different depending on what board you have. The options might look something like this though…

 

100(Mhz)(1/02), 120(Mhz)(3/05), 133(Mhz)(2/03), 140(Mhz)(7/10), 150(Mhz)(3/04), 166(Mhz)(5/06), 180(Mhz)(9/10), 200(Mhz)(1/01).

 

When this option is set to 200(1/01) it means your ram is running the same speed as your FSBHTT. If you lower it then it puts your ram on a ratio which would make it run slower then your FSBHTT setting. You might want to do this if you have poor overclocking RAM, but still want to overclock your CPU. You can still see good gains in performance from overclocking on a divider.

 

Here is the way you calculate out how fast your ram is running using the 9/10 ratio and a 300HTT speed:

 

300HTT / 10 * 9 = 270mhz memory speed.

 

So its always...

HTT speed divided by the second number in the ratio and then times the first number in the ratio.

 

Here is one more example, this time we will use 270HTT with the 5/06 ratio.

 

270HTT / 6 * 5 = 225mhz memory speed.

 

Now for the lazy people I have a nice little app here that was made by goddh0r.. You can input your htt, cpu multi and divider then it will tell you what speed your ram is running at.. (Thanks to Wildstyle for hosting this file)

 

A64MemFreq 1.1 by goddh0r

[THunDA]

Now we are getting closer to the fun part of overclocking.. !!

 

But first I’m gonna list some programs that you will NEED with links to download for testing stability. Everyone has their favorite program for testing but these are my favorites lately:

 

Memtest ver. 1.51

http://downloads.guru3d.com/download.php?det=996

 

Prime95 ver. 24.11

http://www.mersenne.org/gimps/p95v2411.zip

 

SuperPi

http://superpi.radeonx.com/

 

OCCT

ftp://ftp2.ocbase.com/ocbase3/OpenBeta/OCCTv0.91.exe

 

3dMark01, 3dMark03, 3dMark05

01 = http://downloads.guru3d.com/download.php?det=320

03 = http://downloads.guru3d.com/download.php?det=576

05 = http://downloads.guru3d.com/download.php?det=874

 

**Important note**

You will NEED some type of temperature monitoring program to watch your temps. Most motherboards come with a utility for this or you may be able to download it from the manufacturer’s site. Sometimes these temp programs are not the most accurate and I would really recommend to check around from others that use your moboCPU combo and find out if they are at least close.

 

Here is a link to a thread by Soundx98, with a config file for motherboard monitor that he was nice enough to make which works great with DFI NF3 and DFI NF4 mobo's..

 

http://www.dfi-street.com/forum/showthread.php?t=6798

 

Finding the max of your CPURAM

 

Finding the max of each component is very important in overclocking. Many people think they can just up the HTT and be done with it, but that’s not true most of the time because then you might get instability and not know what the source is. To me, not finding the max of each component is like fighting a group of people at once when you have the option to fight them one at a time. The first thing I like to do is find the max of my CPU and then my ram.

 

To find the max of your CPU you want to take out your other components as variables, so this is what I do:

 

CPU/FSB Frequency Ratio (CPU Multi) to default. Do NOT use the auto setting! Manually set it to whatever your default multi is.

 

LDT/FSB Frequency Ratio (LDT Multi) to 2.5x or 3x.

Setting this lower right now will make sure that your total HTT speed doesn’t cause instability.

Wildstyle says.. You are freely able to lower this value and not lose performance because even with a HyperTransport Bus frequency of 200MHz (LDT = 1x), due to the nature of the HT architecture, there is still enough bandwidth available to transfer data between CPU/RAM/HDD without bottlenecking; and at 200MHz the theoretical bandwidth limit is still higher than that of AGP 8X, so video card performance is not affected either.

LDT/FSB Frequency Ratio (Ram Ratio) to 100(Mhz)(1/02)

This is much lower then you should ever set this but it will make sure your ram is running way under spec and wont be causing you any problems at this point..

 

CPU VID (Voltage Identification) Control (CPU Vcore)

This is a tricky one.. Its gonna depend on how good your temps are and how far your willing to take it. For 90nm cores (i.e. Sandiego, Venice, x2, Winnies) its best to stick around 1.6v-1.65v MAX, For 130nm cores (i.e. Clawhammer, newcastles) you can go a little higher to 1.7v-1.75v but always make sure temps are good. If you have extreme cooling like water or phase then you can take the voltages higher. You could also try to see how far you will get on stock vcore first or just bump it up from the start. This is totally up to you and what you feel comfortable with. Some A64 CPU’s actually overclock better with less voltage that’s why its good to start off lower to find the max of that and if your unhappy or want more then you up it from there.

 

**Important Note**

Load is when your CPU usage is at 100%. This will happen while playing games and also when running the stability testing programs I listed above, especially OCCT and Prime as they will make your CPU usage 100% for sure. Load temps for CPU’s should always stay at or below 50c, a little over 50c wont hurt either but lower is always better.. If your temps are exceeding 50c by a lot then you either need to upgrade the cooling or lower your voltages andor clocks.

[THunDA]

Ok.. now that you lowered the LDT multi, put your ram on a ratio, set your default CPU multi manually and decided what vcore you want to start with its time to start testing..

 

You want to start raising your HTTFSB in 10-15mhz increments and in between each move you want to boot into windows and run the SuperPi 32m test. It will take about 30-45 mins normally. If it passes that then keep upping the HTT until SuperPi gives an error then back it down a few MHz (1 or 2) at a time until its stable again...

 

**Remember to monitor temps**

 

Once you find the highest spot where SuperPi is happy you want to run the OCCT 30min test (Not the torture option.) This test is a little tougher then SuperPi and if OCCT fails then lower your HTTFSB 1 or 2mhz until you can pass OCCT..

 

**Remember to monitor temps**

 

At this point you can run each 3dmark bench to see if they complete without a crash or error. Don’t worry about the scores being low, this is because we slowed everything else down except the CPU.. If they all pass then we are off to Prime time.. hehe. This is the last thing you will run to test the stability of your CPU . Many people are going to have their own amount of time they like to run prime. Personally I run it for 8-10 hours but some like to run it 24 hours before they consider their system stable. I can understand running it for 24 hours when you’re comparing between peoples stable clocks to make sure they are all stable with the same guide lines but I never felt the need to run it that long for my rig to be stable for ME..

 

If prime fails then back off on the HTT/FSB some until it passes at least 8 hours without errors.

 

CONGRATULATIONS !!

You just found the max mhz of your cpu..

 

Next thing we are gonna work on is finding the max of your ram.. Here is how you are gonna setup for that:

 

CPU/FSB Frequency Ratio (CPU Multi) This we are going to lower to the 7x multi.

 

LDT/FSB Frequency Ratio (LDT Multi) Keep this at 2.5x or 3x just like it was when testing the CPU..

 

LDT/FSB Frequency Ratio (Ram Ratio) Put this at 200 (1/01) so it will be running the same speed as your HTT now.

 

CPU VID Control (CPU Vcore) You can leave this at the same setting you decided to leave it at during your CPU testing.

 

Now you have the CPU vcore like it was during the CPU testing, the CPU Multi to 7x, the LDT Multi to 2.5x or 3x, and the RAM ratio set to 200 1/01..

 

There is only one more thing that you need to do before testing the ram: Learn about timings!! I’m not gonna go deep into this but I’m gonna suggest what timings are popular with some known types of ram chips. Before you go ANY further I highly suggest you read this ram guide by johnrr6 at DFI Street..

 

http://www.dfi-street.com/forum/showthread.php?t=11397

 

Its also a good idea to do some research to find out what type of chips your ram use.. It will give you a better idea where to start off with timings and voltages.. Here is a link that might help you find what chips are on your sticks of ram..

 

http://xtremesystems.org/forums/showthread.php?t=50010

 

Here are some timings I can recommend without getting deep into the full page of memory timings that my DFI board has.. hehe

 

TCCD

CPC- Enabled ( 1T )

Cas- 2.5

tRCD- 3 or 4 for more stability

tRP- 3

tRAS- 8

 

BH5,BH6,VX,UTT

CPC- Enabled ( 1T )

Cas- 2

tRCD- 2

tRP- 2

tRAS- 8

 

No matter what ram you have timings are never written in stone. They NEED to be tweaked, period ! Always remember that just cuz “Joe Overclocker” says his TCCD runs at 300htt with 8-3-3-2.5 timings doesn’t mean yours will even if it’s the same ram brand, model, revision, production week.

[THunDA]

Time to start testing your RAM !!

 

With the above settings you want to start raising the HTTFSB 5-10mhz, and in between each raise you are going to run about 25 passes of memtest (Test #5 only for now) Once you get errors there are a few things you can do here:

 

1- Lower the HTTFSB until its stable.

2- Raise the Vdimm (RAM Voltage) to see if that makes it stable, but remember some RAM doesn’t like a lot of vdimm and it could damage them.

3- Loosen the timings to make it more stable.

 

Which option you choose is pretty much up to you and how much you know about overclocking RAM. I can’t stress it enough to read all you can about overclocking because there is so much info out on the net between guides and forums alone.

 

Now once you decide what option you are taking, continue testing with memtest #5 until you’re at your max for the ram without errors. Then I would suggest running all the tests in memtest overnight - 8-10 hours.

 

If it passes the long test then you want to leave those settings like they are and boot into windows. It might not be stable in windows even if it passes memtest though. I’ve noticed with a64’s that I could pass hours of memtest sometimes but have instability in windows. If you aren’t stable then you need to either give more vdimm, loosen the timings or back off the HTTFSB some.

 

If you do make it into windows I would run 32m SuperPi, 30min OCCT, 3dMarks and then Prime95 overnight, just like we did to finalize the CPU’s max. If it fails any of these you have a few options…

 

1- Lower the HTTFSB until its stable.

2- Raise the Vdimm ( Ram Voltage ) to see if that makes it stable.. But remember some ram doesn’t like a lot of vdimm and it could damage them.

3- Loosen the timings to make it more stable.

4- Settle with what you have so far.

 

If you decide to go with one of the options from 1-3 then keep repeating the tests until you are happy and stable.

 

CONGRATULATIONS !!

You just found the max MHz of your ram..

 

 

Now that you found the max of your CPU and ram it should be a little easier to clock it together..

 

Lets say your CPU maxed out at 2800mhz with its default multi of 12x.. But your ram maxes out at 250mhz..

 

12x 250 = 3000mhz.. That won’t work ..lol..

 

11x 250 = 2750mhz .. That will work but your cheating yourself 50mhz of CPU power.

 

12x 233 = 2796MHz .. That will work and get you closer to the max of your CPU. And running the ram little slower then the max you found before to achieve the higher CPU MHz might also allow you to tighten up the ram timings a little.

 

Now there is always the option to use a divider for your ram which will get you closer to your CPU and RAM’s max....

 

10(CPU multi) x 278(HTT) = 2780mhz (CPU speed)

 

If you use a 910 divider with this config…

 

278 10 x 9 = 250mhz (mem speed)

 

Whatever you decide there really isn’t a right or wrong way to do it. The only way to find out which way is best for you to run is test test test!! Run benchies with different configs and see which performs the best.

 

This is just a small portion of overclocking.. There is much more to learn but I hope this helps some of you get a better grip on where to start with your A64 system. It took me a lot of time to figure it out myself, it just takes patience.

 

 

Here im gona list some links to things I suggest you read..

 

Confused by HTT? LDT? FSB? A64??? READ THIS!

 

which bios is best for you? some things to think about in overclocking..

 

Power Supplies for DFI N4 Ultra/SLI Mobos

 

Forum Rules - Please Read

 

Important Info (critical!)

 

Important Info (non-critical)

 

After you rig is stable.. FOLD FOR DFI-STREET !!

 

**Disclaimer**

Overclocking can possibly damage your hardware when not done with care.. Sometimes even when care is taken things can get damaged since you are pushing things past the limits they were intended to run.. So Me ( THunDA ) or DFI-Street will NOT be responsible if you damage any of hardware..

[ZoKi]

Excellent guide. Thank you

[CJ4]

Good job!

 

CJ

[OldGuy]

Very cool. Still kind of a noob and it's nice to see some confirmation I've been going about it in somewhat proper fashion.

 

There is no "absolute" right way but there sure are alot of "wrong" ways :nod:

 

Thanks Thunda!

[THunDA]

There is no "absolute" right way but there sure are alot of "wrong" ways :nod:

 

Thanks Thunda!

 

HAHA.. thats funny..

 

Thanks for the kinda words all.. Im hoping this will help some people out..

 

And be sure to check back because I will be adding other things as they come to mind.

[pers]

Very nice guide Thunda.

 

I'm new to all this overclocking lark. So find this information very handy

[CJ4]

May want to put in that the max HTT is around 1000.

 

CJ

[THunDA]

May want to put in that the max HTT is around 1000.

 

CJ

 

Good idea CJ.. I will add something about that in a bit..

 

It was hard to try and write it up all at once and im sure there will be additions when either I think about it or someone reminds me..