2.4B@2798 not stable

Hi. Here's my rig:
430W PS
2.4B
512MB XMS Corsair C2 3200
Abit BE7-Raid 845PE

I can get it totally stable at 150 fsb. With +10% voltage it'll do 2798 without any jamming but eventually fails Prime95. Apparently the CPU gets all the way to 54 degrees. I can't do anything over 155 fsb. It won't even boot. I know the memory is not the culprit after running it 1:1, so what is?

Did you try to raise the CPU vcore? Just a thought...

The thing is this boot problem happens even if it isn't overclocked. It's not that at 2798 it is more unstable. It runs prime for a few hours before failing... at 2.7 it doesn't fail ever, but it still does spontaneous reboots and crazy stuff like that every few days. Sometimes it refuses to POST and gives me a BEEP followed by two shorter beeps. What's that?

I have a 2.4b @ 2.81 Ghz and can run 3dmark01se for 9 hours straight with 0 problems.

Prime95 however fails pretty quick. I have been running this setup for almost a week and have experienced 0 problems.

SYT_Shadowfax said:

The thing is this boot problem happens even if it isn't overclocked. It's not that at 2798 it is more unstable. It runs prime for a few hours before failing... at 2.7 it doesn't fail ever, but it still does spontaneous reboots and crazy stuff like that every few days. Sometimes it refuses to POST and gives me a BEEP followed by two shorter beeps. What's that?

Click to expand...

Well now we have a complete new story. Check your motherboard manual to see what those beeps mean.
It could be many different things that cause your PC actin like that, e.g faulty RAM, CPU, mobo, PSU...

Shadowfax, you've got some pretty good components there. If that BE7 won't take you to 3 gig, nothing will.

Remember at 10% over, the board still undervolts around .050-.075, so you may not be running as high VCORE as you think. I presume your 2.40b is not a C1? But even C1s have trouble passing Prime when overclocked.

Try more voltage. Also check your ram with Memtest. Make sure the #4 (CPU) and #5/#6 (ram) tests are totally clean. XMS3200 is good stuff, but maybe you got a faulty stick. Spontaneous reboots sounds like the ram is erroring out, but it could also be the CPU.

Check both the #5 and #6 test for the ram (or the whole loop). Some guys running crazy stuff like DDR500 or something are just looping the #5 test to check the ram but I found the #5 will pass but have to drop 10 mhz down to get the #6 test clean.

i must be pretty lucky. i have a 1.6a thats runs fine @2720mhz

Clevor: I'm aware of the undervolting. At +5% (which is what I run 2.7 totally stable in Prime) it does around 1.5 core under load, which should be default. When I try to do 2798 I run at 155 fsb and +10% voltage. It runs Prime until the chip gets to around 56º and then errors occur. I imagine they're due to the CPU being too hot and should get fixed once i get a decent fan on my heatsink.
The problem isn't running Prime95. It's that sometimes it won't boot and gives me a BEEP followed by two shorter BEEPs. Then I have to clear CMOS and start all over again. The wierd thing is it does this even at 2.7 (where it's 100% stable per Prime95) and even at stock speeds. I have a 120mm fan cooling the memory and the northbridge, so it shouldn't be that.

Thank you for the memtest info. I'll try it out as soon as I can. When I started overclocking I tested out the memory with the mem68 program at 412mhz and stock voltages. It looped the tests for almost a whole day without any error messages. But I'll try again anyways.

SYT_Shadowfax said:

Hi. Here's my rig:
430W PS
2.4B
512MB XMS Corsair C2 3200
Abit BE7-Raid 845PE

I can get it totally stable at 150 fsb. With +10% voltage it'll do 2798 without any jamming but eventually fails Prime95. Apparently the CPU gets all the way to 54 degrees. I can't do anything over 155 fsb. It won't even boot. I know the memory is not the culprit after running it 1:1, so what is?

Click to expand...

well not all 2.4B's hit high overclocks.. I've tested tons of them.. NONE did 3GHz... and one only did 2.5GHz... so it's probably the CPU.. but you are running a bit hot for only 2798MHz.. try to get those temps below 50C and try again...

If it was cpu the bios would start the machine at default clock rate and report "cpu failed due to overclocking". The beeps are ram. Loosen up your timings and/or apply more voltage to the ram. Start and the least agressive timings and work the setttings down one by one one step at a time. Chances are good there is just one or two settings that are too aggressive.

My manual makes no reference to what different beeps mean. That's the first thing I did: go to troubleshooting and see if there was a solution.

Yesterday I booted at 161 fsb, which is 2.9Ghz. The ram is running C2 2-5-3-3 at 3:4 (430effective). It seemed fine with the speed once I gave it 2.7V. Anyways, it did prime95 stable until the temps rose over 65 degress and I got a hardwaremonitor warning.
My system is definitely running WAY too HOT! I've put it back to 2.7, kept the ram at 2.6 and it's been working fine. I'm going to change the cooling and maybe then it'll run 2.9 stable.

About the cooling: Will a 120mm 54cfm fan blowing through a 120/80 adapter and the external casing of another fan deliver more than 15 cfm? Because the silent fan i have on the heatsink just does 15, which is way too little! Here I can't buy 70mm fans (looks like I'm in the dark ages here in Spain) so I can either use the adapter or keep the 15cfm silent fan. What do you guys suggest? I have 2 intake and 2 exhaust (apart from the PS) 80mm fans. That should give decent airflow.