I have an old p5n32e-SLI, and have just recently bought a radeon hd6850 to upgrade my old 8800gt. I was hoping to OC in order to increase performance and get a year or 2 more out of my computer before being forced to upgrade. I primarily use the rig for gaming.
I'm fairly horrible when it comes to computers, and I consulted several overclocking guides, including ones specific to my mobo. Most of the guides have fsb recommendations that are below the minimum my BIOS says I should input, BIOS says minimum 500 yet my multiplier is 9 - I'm confused =/. Also my RAM sticks say 5-5-5-18, and most guides say 4-4-4-8 or 12 .Any advice on OC'ing this setup would be great.
Most of the guides have fsb recommendations that are below the minimum my BIOS says I should input, BIOS says minimum 500 yet my multiplier is 9 - I'm confused =/. Also my RAM sticks say 5-5-5-18, and most guides say 4-4-4-8 or 12 .Any advice on OC'ing this setup would be great.
The 680i BIOS work a little differently from the Intel P45 BIOS. With the 680i BIOS, you change the FSB clock, not the FSB freq.
Definition time (attention purists, I'm talking about DDR2 and I'm simplifying a little ):
Core2 CPU's use a frontside bus (FSB). The FSB is a thing with two main characteristics: speed which is usually defined in MHz and width which in the Core2's is 64 bits wide. We are concerned with the speed.
Using the Q6600 as an example, the FSB frequency is 266 MHz. The matching DDR2 memory clock for that frequency is 533 MHz (266 X 2). DDR2 memory transfers two chunks of data for each bus cycle, hence double the frequency. So, to run 1:1 at an FSB of 266 MHz, we need DDR2-533 RAM. What CPUZ does is a little confusing. It will tell you that the memory frequency is 266 MHz for a 1:1 ratio.
The FSB clock is 1066 MHz (266 X 4). The bus is "quad pumped". It transfers 4 chunks of data into and out of the CPU each cycle. So each FSB cycle generates 4 FSB clocks.
Now, if you increase the FSB frequency to 333 MHz, the corresponding memory clock is 667 MHz and the FSB clock is 1333 MHz.
I always run my memory at 1:1. That is the FSB freq to mem freq ratio of one to one. That means that the memclock is twice the FSB freq. It's a little confusing. Running memory slower costs performance. Running memory faster does not give you much if any real world performance increase and it can lead to higher instability.
Any Q6600 will run at 3.0 GHz with the stock cooler. So you want to set the FSB clock to 1333 MHz. You should see 333 MHz in a window somewhere. Then set your memory to Linked. That will put your memory exactly instep with your CPU.
Take your CPU voltage off Auto.
Now try to run Prime95 small fft's to test your CPU overclock. If it passes, great. If it fails, go into the BIOS and increase the CPU voltage 0.1 volt. Retest.
Speeds past 3.0 GHz will require better cooling.
You should be able to get up to 3.3 GHz (367 MHz FSB freq, 1467 MHz FSB clock, 733 MHz memory clock).
While you are doing all of this, you need to monitor your CPU temperatures under Prime95 loads. Stay under 70 C. And do not increase CPU core voltage over 1.50 volts.
Different chips have different timing characteristics. 4-4-4-12 and 5-5-5-15 are both very common DDR2 timings. Don't worry about variations in the numbers. Lower numbers are faster and more expensive. Core2 CPU's are not affected much by memory timing differences. If you plugged 4-4-4-12 RAM in, you would not notice any difference in performance.
Thanks a ton, that made everything so much more understandable. Couple more questions if you don't mind, however I think I'm starting to get a newbies grasp on it. My RAM is DDR2-6400 (800mhz) so should I be running unlinked with the inputted 'Actual MEM (DDR), MHz' - 800? When I link at 1:1 both the FSB (QDR) and the Actual MEM are 1333, but that's not the value my RAM has printed on it.
Right now my OC screens look like this:
FSB Mem Mode - Linked
Mem Ratio - 1:1
FSB QDR - 1333
Actual - 1333
Mem - Linked
Actual - 1333
My RAM sticks say 5-5-5-18 on the back, but I've put in 5-5-5-15 (2t) since most guides say that is the setting I should use.
Concerning voltages, is vcore the only setting I should change? I know p5n32e's have had heat problems on the NB (anything over 32C) so I'll watch that carefully.
I've followed your suggestions but I still can't get into windows yet with these settings. I really do appreciate your help, your easy to read explanation cleared up a ton of the technical stuff in other guides.
FSB:RAM ratio of 1:1 is the "happy spot". Slower costs performance. Faster strangely enough doesn't help much and can add to instability, something you do not need when overclocking - or any time else, for that matter.
You either need to run "Linked" or "Unlinked" and manually enter memory settings so that you are running 1:1. In that case, enter (FSB clock/2) for the memory setting. I had to do that with my eVGA 680i.
If your memory says 5-5-5-18, I'd put in 5-5-5-18-2T. The difference in performance would be unnoticeable and you might need the settings to make your system work.
Based on my 680i board, the MCP tends to run really hot. Upper FSB limit of my board was 442 MHz. 443 did not work. Overvolting the MCP enough to reach that freq gave me almost 90 C MCP temps. I lowered MCP temps to about 70 C by dropping back to 400 MHz.
You can try all of this, but over the years I have seen people here have difficulty overclocking nForce 600 with Q6600/6700 CPU's. You may be one of the unlucky ones.
Just wanted to thank you for your help, I've gotten it stable at 2.85 and 1.31vcore. I'll keep on messing around and pushing it, though if I go higher on the vcore I'll be hitting 70c coretemps. Thanks!
It's weird, 2 of my cores run about 10 degrees higher than the other two while running prime. The case is a large coolermaster, don't remember the model - got some aftermarket fans added in there. It's only the 2 cores that go high, the other 2 cores stay in the 50s, maybe hit 60.
Got settled on a 2.8ghz @ 1.31vCore - linked 3:2 ratio and mem voltage of 1.9, wouldn't boot with 1.8 if I overclocked the memory at all