Just watercooled my nb/sb but my OC isn't any better

[redj41]

Ok, over the weekend I installed bitspower black freezer wateblocks on the nb/sb and mosfets of my 780i. I already have the cpu watercooled by a danger den block. My previous max overclock with any stability was 4.62 GhZ. I was able to boot a couple times at 4.7-4.8, but not with any stability. I can run 4.5GhZ all day without an issue. At 4.05 GhZ the MPP, SPP, and CPU temps are all about 40C under load (it's about 70F in my room). Now that everything is watercooled and at much better temps, I still can't seem to get a better OC. I have an XFX 780i running with 1.4-1.5 volts on the FSB, and 1.46-1.5 volts on the cpu. Memory is DDR2 1066 @ 2.1V and 5-5-5-15 timing (manufacturer specs). Any advice? I'm glad my board is much cooler, but I was really hoping to break 5GhZ suicide and maybe 4.7-4.8 stable. Any advice or help would be awesome. Pics as soon as I can get home and load them up.

[potatochobit]

I dont have any advice for you to go higher on your overclock but I think the point of cooling the NB/SB is to keep from damaging it and keep it stable; you are not raising the max per se by increasing the voltage on the northbridge. in fact, increasing NB voltage too much has negative ramifications I believe and causes instability.

[shiver_8]

Learn about CPU and NB GTL Reference voltages. Your fsb is used to tweak these settings but they are the main basis for stable high-fsb overclocks.

[redj41]

Thanks for the input. I've read up on GTL voltages, but my mobo/bios doesn't support doing much with them (I can increase them, but from what I've read I need to decrease them). I've left the GTL refrence voltages on auto for all of this. I guess now that this rig is done it's time to start saving for an i7 setup.

 

shiver-8 I just noticed your sig says you hit 545x9 @ 1.72 volts! That's really up there. I think my problem may be not enough CPU voltage. I know I have a differenc motherboard, but I haven't passed 1.5v in the bios (actually about 1.48 on CPUID). Maybe this could be my problem?

Edited February 8, 2010 by redj41

[shiver_8]

Yes it is alot of voltage, however you have to remember that the amount of voltage needed in relation to the cpu frequency starts increases tremendously at high speeds compared to 3.6-4ghz. My cpu is stable 4ghz at 1.28v. But yet it still needs 1.72 for 4.9ghz. You can see that there is a large jump in voltage. However for me the jump from 4ghz to 4.5ghz was greater in terms of voltage as with 4.5ghz 24/7 i need 1.52v = .32v more. where as 4.9ghz needs 1.72v = .2v more. So you can see that it varies chip to chip. I've seen a few people hit 4.8 with only 1.4v.

[ccokeman]

ON the 780 and 790 chipsets FSB is really picky when it comes to voltages. Linked and unlinked memory also play into it!

[redj41]

Knowing that voltage doesn't rise linearly with CPU frequency is good to know. I've been doing most of my overclocking based on a linear correlation between frequency and voltage. Thanks again! I had no idea linked and unlinked memory could affect the overclock much, but I don't think I could link my memory without it going nuts. I'll have to play around with it some. Any advice for memory timing while overclocking? Just set it to auto and see what happens, and then maybe go from there? I know that 1066 mHz memory isn't the best DDR2 out there, and anything past a 533 FSB is going to exceed the memory speed. Still, 533 makes for a FSB of 2132 and an overclock of 4.797. Maybe that's the highest I'll get stable? I've hit that mark before (1.48v on CPU, 1.4 on FSB) but only stable enough to run super pi at 1m. OCCT crashed in less than two minutes and 3dmark froze in the spaceship sequence. I really appreciate your guys help with this, as I definately want to break the 4.7g stable barrier. Going to play with some serious voltages soon.

[shiver_8]

NP! I don't have the patience to try to get 4.7 and 4.8 stable i just go for 5 but yeah 4.9 was stable enough for superpi 1M it was somewhere around 9.2