Need help

tommchowat · 19 May 2009 at 13:27

Hi guys,

Need some help with my overclock. Here's the PC specs:

E7400 2.8 @ 3.6GHz
Asus P5KPL-AM motherboard
4GB (2x2GB) Corsair Dominator PC8500 RAM

Basically with the stock cooling I could get it up to 3.6GHz before temperatures got too high. I just bought a new Xigmatek cooler which I'll put in as soon as I've got some thermal paste and enough time. However, I can't get it over 3.6GHz, or I get a no show, then have to turn off the computer and then be told that overclocking or overvoltage has failed.

My current BIOS settings are:

CPU frequency: 344
Multiplier: 10.5
Vcore: +100mA

But my ABSOLUTE limit in the CPU frequency is 344. If I put in 345 then I get a no show. I've tried playing with different frequency/multiplier combinations, for example I've tried 360 x 10 but that's a no show. I can't ever go above 344. I thought it was the RAM that was causing the problem, I had 2x2GB of PC6400 RAM, and I replaced these with the Corsair Dominator PC8500 but no change. In the BIOS I also can't run the RAM at over 800MHz or I get a no show. Tried changing the RAM voltage to 2.1 like it's specified but it doesn't help. Timings are 5-5-5-15.

Can anyone help me get over 3.6GHz?!

Thanks

Tom

Plec · 19 May 2009 at 13:46

There is the possibilty you have reached your cpu's threshold?

I have to run my memory ~200Mhz below stock too to keep my system stable; it's a necessary evil with some clocks.

Is 2.1v the maximum memory voltage you've tried becaue i would, personally, up the voltage to at least 2.2v even 2.3v to see if it gets you better results?

When you say your temps get too hot - how hot is everything getting?

Edit: You could try slackening your timings a little too if the volatge increase is of no help.

tommchowat · 19 May 2009 at 14:09

Thanks for the reply.

The maximum I've tried is 2.1 because I've read that it's the speed that the memory runs best at, but I can try upping it to see if it helps.

Temperatures at the moment reach about 62 degrees with Prime95 under full stress, but that won't be an issue once I put in the new fan and heatsink (probably tomorrow).

I don't know anything about RAM timings and what they mean... can you explain briefly?

Thanks

Tom

Plec · 19 May 2009 at 14:25

As you're overclocking the cpu the memory may well require an extra jolt of juice - just up it by 0.1v. The 2.1v is its recommended volatage at stock settings - it's not unusual to have to up the voltages when overclocking.

Have you upped your vCore? As this is another setting you should be upping if you're having problems.

The above are the first things i would be trying . I would then, if it was necessary, combine them with with reducing the memory frequency and timings if required - but this shouldn't be a problem as you're already at 800.

Here's a useful guide on memory timings - link.

tommchowat · 19 May 2009 at 14:32

Thanks. I just tried upping the memory voltage to 2.2 and I get a no show. My Vcore is +100mA from the standard 1.25, so it's 1.35 now.

I'm just going to look up whether I have the latest BIOS for my motherboard, if not then I'll flash it to the latest version.

EDIT: I just flashed it to the latest version, and it said that it had improved compatibility for 533MHz FSB settings... so really the motherboard should be able to take that?

Plec · 19 May 2009 at 16:06

Try relaxing your memory timings - if you can get it stable with less aggresive timings you may then be able to up the memory's frequency, eventually.

But for now you're obviously just looking to get it stable - knock the FSB down 10MHz or more just so the system is stable and see which memory settings destabalize it?

Edit: Ideally, you would start from a stable base and work your way up in increments - and then alter different settings accordingly. But if you get some success with the above you may as well run with it

tommchowat · 19 May 2009 at 19:31

It is stable at the moment though.

RAM: 800MHz, 5-5-5-15, 2.1V
FSB: 344 x 10.5, 1.35Vcore

With those settings I've verified it's stable. The problem is that anything above 344 for the FSB and I get a no show. Don't really know where to go with this!

Plec · 19 May 2009 at 20:06

That's quite a healthy clock to be getting on with.

I would live with that for a week or so - prime95, memtest it and generally use and abuse it with apps and games. Once you're absolutley sure it's stable at that clock you can then try upping the clocks again - as you'll know that you have deff found a stable platform to revert back to if it all goes t*ts up.

It may be that you're almost at your cpu's limit - but i suspect that with some fine tuning of a mixture of other settings you may get a few more ~100MHz out of it. (and maybe not).

tommchowat · 19 May 2009 at 22:24

I've been at this clock for a good month now, I've Prime95'd and memtested it and thrown games at it and it's fine, so I know I can revert back to it. But I can't actually get further than it for a reason that is beyond me which is the problem!

Plec · 19 May 2009 at 22:42

Try relaxing the memory timings to 6-6-6-18 and up then gradually incease your clocks from what your at - approx 10MHz at a time until it becomes unstable. Drop it back to the last stable setting and stress test it - if it fails drop it another 10Mhz and test again.

Let me know how you get on.

tommchowat · 19 May 2009 at 23:09

I will, thanks for the help.