Question about 1T and 2T Timing

[noxman]

Hello!

 

I've finally received my two G.Skill 1GBLC (Samsung TCCD 431) 512MB modules and installed them.

 

BIOS is the newest official one (I Think 623-3, June 23)

 

I used the following DRAM Configuration (by kakaroto, xtremesystemforums):

BIOS Settings

 

Vddr: 2.7v

Tcl: 2.5

Trcd: 3

Tras: 6

Trp: 3

Trc: 9

Trfc: 12

Trrd: 2

Twr: 2

Twrt: 2

Trwt: 2

Tref: 3072 (200MHz 3.9us)

Twcl: 1

 

Bank int.: Enable

Skew control: 255 +

Drive strength: 7

Data strength: 2

Max. Async: 7ns

Read Preamble: 5ns

Idle Cycle: AUTO

Dyn. Counter: Enable

R/W Bypass: 16x

Bypass Max: 7x

32Bit Gran.: Disable

 

 

(btw, does 255+ means INCREASE, or am I wrong about that one?)

 

but my machine wasn't stable at ANY frequency! Neither @250, neither at 275 and neither at 225. The multiplier for the LDT was 3.0, the CPU was never overclocked.

 

I then tried to increase the voltage for the CPU a bit. (Startup @ 1,425V, VID Control@1,425, special VID contro: AUTO)

 

First question here: why is there a StarUp Value? and why are there TWO VID controls? one to 1.55V and the other to increase this value by a certain percentage?

 

But that didn't help.

Because I was too lazy to test each module in Single-module configuration, I immediately tried to set the Clock per Cycle two disabled, i.e. 2T Timing.

 

Now, the PC is also running stable @275Mhz RAM Frequency.

 

My questions here:

 

1. Is the 2T timing much slower than the 1T Timing?

2. Does that mean (i.e. 1T timing = unstable, 2T = stable) that my processor has a bad memory controller? or must I do something else to ensure that CPU is the problem and not my memory modules?

 

Thanks for help and answers!

[ICON57]

if you feel like its your mem, you should run memtest 5 and 8.

 

i ahve my g.skill running @ 1T 1:[email protected] i followed the same settings from extreme that you did. i did tweak a few of the tweaks...my timing is 2.5 4. 4. 8.

[Wolverine]

1. 1T is just a little slower than 2T (in real life U´ll lose not more than 2-4% of bandwidht)

2. 1T/2T doesn´t mean stable/unstable

U use 2T if U use all 4slots (4x512MB) because A64´s mem controler can´t work with 4 double sided RAM sticks (to much banks to controle)

Or in some case with 2sticks when 1T isn´t stable...

 

Skew control set to Increase and value at 50-100

 

@ CPU voltage StartUp leave @ Auto or set to 1,400v

VID Control@How mich U think U need for stable CPU and special VID control: use to increase voltage.

 

I use start up@ Auto, VID @ 1,425v and VID control @ 104% for my 3000+ @300x9

[Boppo]

First question here: why is there a StarUp Value? and why are there TWO VID controls? "one to 1.55V and the other to increase this value by a certain percentage?"

 

The startup Value is the voltage that is applied to start the computer until your BIOS settings are applied.

 

You have two more settings to allow a wider number of available voltages to shoose from. The first one raises the voltages in larger increments, while the % allows you to make smaller adjustments to get just the right voltage.