View Full Version : New system build troubles

08-18-04, 04:24 PM
I thought i'd make a post here to detail a bit of hassle i got building my new system. My old rig was an axp 2400+ w/ 512mb DDR266 and a ti4200 128mb. I got a 6800gt a couple of weeks ago, but the system above really held it back, so i ordered an a64 3000+, a K8NS non-pro nforce3 250 mobo, and a 2x512mb Corsair value select DDR400 cl2.5 ram kit.

When that arrived i spent a good hour absorbing the instruction manuals, then put it together and put it in my old case, with the same old 430w enermax psu (20A 12v rail). It booted fine, bios said 35c cpu after 10 mins warmup. The ram only detected as 166 though, i thought i'd leave it on the auto speed option in the bios still, it could wait until i had windows reinstalled. That went fine, installed all my drivers, and set the 6800gt back to it's speeds on the old rig, 400/1100. rebooted and went to look at that ram in the bios, changed auto speed to 200, and left timings on auto.

This is where things went seriously foobar, windows loaded fine, so i installed 3dm03 as you do, to check whether things were all working at full speed. Halfway through test 1, it locks, then comes back about three quarter fps of before. At test 2 it spits a memory read error and goes to desktop.

I'm thinking this is a heat issue at this point, so i install mbm5, the mobo isn't listed, so i set up the sensors manually. It says my cpu is at a toasty 71c! sensor 2 is at 55c also, which i assumed to be the northbridge chipset, 11v is at 11.2, and the 5v wobbles from 6 to 2. Yeah, you bet i went to turn it off! However i had the thought to double check in the bios after the reboot, that said 43c for the CPU, and all the voltages show as "OK" levels.

At this point i won't explain all that happened next, suffice to say i spent the next two days scouring the net and trying assorted bios settings. With the RAM sticks in slots 2 and 3 i could only run DDR333, aka 166 in the bios, or 2t timings at DDR400. They were both equal in terms of bandwidth, around 2.6GB/s.

Researching this i found a piece of information that isn't very well known about the s754 a64's onboard memory controller - [b]it's only supposed to work at 200fsb with no more than one DOUBLE-SIDED dimm in the system[\b], any further dimms should be single sided, and two double-sided dimms will force the controller to run 166fsb by default.

So that explained the ram errors. The high temps are due to gigabyte using a slightly odd variation for the sensors in the bios, so mbm5 and nvidia system utility give bad temps. Anyone with my board and possibly other gigabyte K8NS variants should use the Gigabyte Management Tools on the included cd to get accurate cpu temperature and voltage levels.

The slowdown in 3dm03 prior to the crash to desktop, i found out to be that my 12v rail is weaker with the new cpu, at about 11.7v under full cpu load and gpu load with a cd in the drive being benchmarked. Setting the 6800GT to 375/1100 instead stopped it from dropping to throttle mode and fixed that.

Problems identified, i was ready to send back the ram and mobo for single sided dimms and a board with more recognised sensors. I thought i'd give things one more go though, now the 3d card was stable and i knew the cpu wasn't burning up, it'd be easier to test out the ram properly. I moved the sticks to slots 1 and 2 to try to reduce the distance from the cpu and therefore the controller. Then i noted the timings that were stable at DDR333 with 1t timings, and forced 200 fsb, only to see that the timings were misdetected now, and not what the SPD should say. So i set them manually to the DDR333 timings. Got to windows, expecting opera or something to crash from errors as usual when i tried 200fsb, but things were working fine. I memtest86'ed it and got a 100% pass, benched it in windows, no crashes or errors. So basically the ram was fine now.

And it's been fine all day today too, after leaving burnintest v4 pro running all night without issue.

In fact, i now have it running at 440 mem, 4x HTT, 2200mhz cpu. The cpu is undervolted to 1.35 volts despite the overclock, to reduce the heat output. I fan-mated the stock AMD fan to 2500rpm, and replaced the 40mm fan on my 6800gt with an 80mm @ 5v. The system is now barely audible (the 2 fans at 5v and 7v in the psu make the most noise).

I found the best way to push temps and voltages was to run rthdribl alongside burn-in-test pro on a lower priority running it's cpu, mmx, memory, hd, and dvd tests. Here's where i'd like a second opinion, with everything running above, my cpu is 44c, with an 11.66 12v rail. Does that sound about right for an a64 at 2.2ghz?

Bit of a long post, but it might save someone else the stupendously annoying two days i've just had for the lack information about the system i had built. I'm making a little post in the 6800 series forum about the 6800gt fan mod.

Oh regarding the system change, from old to new, in benchmark figures. (old - axp 2400+ 266FSB 512MB ti4200 128)

3dm03 - old = 1700 - new = 11700

Aquamark - old = 16000 - new = 62000

doom3 demo1 - old = 24fps (medium, 1024x768) - new = 64fps (high, 1600x1200)

So yeah, despite the enormous hassle, i'm very happy with it now. :D

08-18-04, 04:45 PM
nice job m8... :thumbsup:

perseverence pays off... as does ingenuity :D

post some pics of your mods :) seems to be pretty kewl overall...

congrats on the setup...

08-18-04, 05:16 PM
i'll have to make some pics tomorrow, as someone's requesting some for the 6800gt mod i made a thread about in the 6800 forum. Right now i'm just enjoying the new rig, and the silence. :D

Oh i notice you've an a64 3400+, what kind of load temp do you see? my idle is 35c btw, 44c and occasionially 45c loaded temps. I've really no idea what the average is for a64's, and googling just gives me people complaining of 60c+.

By the way, thanks. :)