OCZ PC2-6400 SLI-Ready and P5KC FSB

[polymorphic]

I'm having trouble understanding what's going on with my system's FSB. My sig lists my components. I've tried setting the voltage and timings in the bios, but CPUz always shows the memory's fsb running at 320MHz instead of 400MHz, which it is rated at. From what I've been reading, it looks like in order to get my memory to run at the rated 800MHz dual channel fsb, I would have to overclock the CPU? I guess I'm not fully understanding what needs to be set in the bios, maybe.

Current bios settings are all auto except that i've tried setting the RAM to 2.0v, setting the timings to the rated 5-4-4-15 and 5-6-6-18, CPU fsb is set to 333MHz. I've also set all settings to Auto for SPD and CPU. System runs completely stable with any setting, too.

[polymorphic]

Looking through my bios now, I notice that any fsb/cpu multiplier I use results in the E8400 only running at either 2.14GHz or 3.4GHz. I can't find a way to get the CPU to run at 3GHz. I guess either I don't understand the bios, or my mobo or CPU is bad. Anyone with any experience with the E8400 and P5KC?

[fvbounty]

Originally Posted by polymorphic

Looking through my bios now, I notice that any fsb/cpu multiplier I use results in the E8400 only running at either 2.14GHz or 3.4GHz. I can't find a way to get the CPU to run at 3GHz. I guess either I don't understand the bios, or my mobo or CPU is bad. Anyone with any experience with the E8400 and P5KC?

My system runs at 2000 mhz when I'm not using my system very hard and when I'm gaming of any other cpu intensive program it steps up to 3000ghz, you probaly have Speed Step enabled in the bios like I do. Its so when you don't need the power it saves energy and everything runs cooler! I think its called Speed Step?

[3 of 7]

I'm not sure if this applies, but on my test rig (D875PBZ) with DDR 400 ram.. If you run the sticks in dual channel mode with the board set to auto, it defaults to 320... According to the manual this is the way it's supposed to be..

[polymorphic]

Interesting. Well, I know speedstep is enabled, but I have watched the multiplier jump from x6 to x8 in CPUz and when it steps up to do work, it steps up to 2.4GHz. When it's done it steps back down to x6 @ 2.14GHz. I've been doing some reading, and it seems I didn't understand the cpu ratio/fsb afterall. When I get home I will set the fsb to 333 and the cpu multiplier to 9 and see what bloats.

Is this method correct? Am I understanding it right? 333fsb x x9 multiplier to get 2997MHz, effectively 3GHz. Also, I did happen to get a 400MHz fsb for the RAM, but never could get the proc above 2.4GHz even when it was busy.

[ctal]

Your last post sounds like you are headed in the right direction.

I think that the anomalies you have described are the result of running "Auto" for "CPU Ratio Control" and for "DRAM Frequency." Set "DRAM Frequency" in the bios to "DDR2-800MHz" (if I'm interpreting your memory type correctly), instead of "Auto." Set "FSB Frequency" to 333 MHz, which it sounds like you've already done (and as you probably realize that corresponds to FSB 1333MHz as defined on a quad-pumped basis). Then set "CPU Ratio Control" to 9, as you are intending to do, and that should put the CPU internal clock rate at 3 GHz when it is under load. I think the minimum multiplier value is 6, so I would expect that the CPU clock would be 2 GHz under no-load conditions.

Regards,
-- Al

[polymorphic]

Originally Posted by ctal

Your last post sounds like you are headed in the right direction.

I think that the anomalies you have described are the result of running "Auto" for "CPU Ratio Control" and for "DRAM Frequency." Set "DRAM Frequency" in the bios to "DDR2-800MHz" (if I'm interpreting your memory type correctly), instead of "Auto." Set "FSB Frequency" to 333 MHz, which it sounds like you've already done (and as you probably realize that corresponds to FSB 1333MHz as defined on a quad-pumped basis). Then set "CPU Ratio Control" to 9, as you are intending to do, and that should put the CPU internal clock rate at 3 GHz when it is under load. I think the minimum multiplier value is 6, so I would expect that the CPU clock would be 2 GHz under no-load conditions.

Regards,
-- Al

I did have everything set as you stated except for the multiplier which was set to 8, which would affect ~2.6GHz. Also, I was changing the multiplier in the bios expecting to see the CPU reflect that, but it's apparently not on-the-fly. I do know that a 400 fsb with an 8x multiplier doesn't boot, though.

[ctal]

Originally Posted by polymorphic

I was changing the multiplier in the bios expecting to see the CPU reflect that, but it's apparently not on-the-fly

I would think the reason you don't see an on-the-fly change is the speed step function the others have mentioned. Turn it off temporarily in the bios, if that is possible (I'm not sure if it is or not), set the FSB to 333 and the multiplier to 9, and you should be running at 3 GHz. If you can't turn off speed step, then after you set the FSB and the multiplier to these values try running Prime95 or something that will heavily load the cpu, and see where you stand.

Regards,
-- Al

[polymorphic]

I've downloaded OCCT to stress the CPU. In the bios I set the fsb to 333, set the multiplier to 9, RAM to DDR2 800 and rebooted. I left the speedstep options enabled. Looks like my fsb is reporting 266mhz and at idle, my proc is running at 1600MHz, at 99% load it ramps up the multiplier from 6 to 9 and I get 2400MHz. FSB for memeory is still at 320MHz. Now I'm really confused.

[ctal]

Yeah, that's confusing. Perhaps after rebooting, go into the bios again and verify that your settings were saved properly. I had a problem a while back with an older Asus board that caused setting changes to not get saved properly. Also, are you using a recent version of CPU-Z?

Regards,
-- Al

[polymorphic]

I'm showing CPUz as v.1.44.1 February 2008. I've rebooted multiple times and the bios shows my settings, but the CPU still shows as running an FSB of 1066 and CPU speed as 2.4GHz.

[ctal]

Not sure what to make of that, but a couple of things to check come to mind. Does the bios post screen also show only 2.4 GHz? Does Windows Control Panel/System screen also show only 2.4 GHz? Also, perhaps you should try removing one stick of memory and changing the memory settings to something extremely conservative, to verify that memory marginalities are not causing the crash-free bios to throttle back the fsb (just a guess; I'm not familiar with how Asus' latest crash-free bios provisions actually work).

-- Al

[polymorphic]

Winders is showing it as e8400 @ 3GHz, 2.40GHz. The bios shows it as 2.4GHz on POST.

I just flashed using the asus afudos utillity to their latest 1001 bios, which does give me many more options for overclocking and RAM config. But, it's doing the same thing where it shows only an fsb os 1066 and 2.4GHz even after setting 333 with 9 multiplier. Strange. I'm beginning to think I have a 2.4GHz E8400...

[polymorphic]

Holy crap! Whew. After all that pain I'm finally up to 3ghz @ 800mhz fsb. Seems that I never reset my cmos after the bios flashes and that's all it took! Thanks for the help guys!

[ctal]

Outstanding! Thanks for letting us know.

Regards,

-- Al