Overclocking Disaster!!

bfar · 11 Oct 2006 at 23:23

I got a new PCI-e mobo Gigabyte Ga-K8ne2for my old s754 a64 3400+. I put in an x1900xt which is really nice, cause its super fast and I can port it over to my upgrade after xmas :-)

I'm more than happy with the gfx card, its awesome, and a great little overall upgrade to keep me going a few months.

There is one problem though - I cannot do any overclocking whatsoever. I've done this many times before, I know what i'm doing - I've dropped the HT Bus to 3x, used a memory divider and slackened the timings, set the PCI-e speed at 100mhz.

But if i even change the bus speed to 205, than prime 95 fails almost instantly. You can also see some mild visual artifacts in doom3.

The vcore voltage looks a little shaky in CPU-z and Speenfan, bouncing between 1.45 - 1.49. My CPU requires 1.5, but I've always assumed thats a max value. I've no other way to test the voltage.

I'm wondering if the PSU is stretched. I'm using an old Tagen 480 with a converter to plug 2 molexs into a 6 pin PIC-e power adapter. The x1900xt is probably sucking the life out of this thing :-/

Is it possible its the PSU? Anyone had any positive experiances from changing the PSU? I have to get a new one next year anyway. I can do it now if it adds value to this system.

Edit - I used to get 2.4ghz out of that CPU on my old mobo easily.

Bomag · 11 Oct 2006 at 23:42

If your A64 3400+ is a clawhammer (1mb cash) then it will need at least 1.5v to run at stock reliably. I have a 3200+ which will run at 2150 at 1.55v and 2200 at 1.6v.

The easy way to check is to put the cpu multiplyer to the lowest setting (5x) and overclock the FSB to 210. If it works ok then you need to increase the volts to the cpu.

bfar · 12 Oct 2006 at 00:41

Bomag said:
If your A64 3400+ is a clawhammer (1mb cash) then it will need at least 1.5v to run at stock reliably. I have a 3200+ which will run at 2150 at 1.55v and 2200 at 1.6v.

The easy way to check is to put the cpu multiplyer to the lowest setting (5x) and overclock the FSB to 210. If it works ok then you need to increase the volts to the cpu.

Yes it is a clawhammer. This is interesting for two reasons. I did exactly as u suggested, including dropping HT to 3x and a memory divider. Everything works fine, including prime 95. The crazy thing is that gaming performance hasn't changed!!! Either the GPU is phenomenal, bottlenecked, or something is going wrong at stock speed.

This is an a64 running at 1.05ghz, and FEAR is super playable at 1280*960 4af 4aa at more or less full detail!!

I have a "hammer vid control" in the bios, which allows me to select up to 1.55v but it seems to make no difference to the voltage.

pastymuncher · 12 Oct 2006 at 10:13

I had the 3400+ Claw and i could'nt get the damn thing past 2.4ghz no matter how much voltage i gave it. It was the worst clocking chip i have ever owned. Try giving it more voltage. You would need to drop the HT multi anyway for overclocking.

mikeymike · 12 Oct 2006 at 10:30

aaaages ago i bought a s754 3400 DTR with hopes of a nice OC, it wouldnt budge past a 100mhz OC even with .2 extra v through the core, sold it the next week, that was my one and only forray into s754

pastymuncher · 12 Oct 2006 at 14:18

There's absolutely nothing wrong with the 754 socket in itself. Just check my siggy for proof. It's just that the 3400 Claw does'nt seem to be a very good clocker. Maybe it's a voltage thing, i just don't know. The DTR's depend mostly on the mobo.

My 3700+ Claw will max out at 2.795ghz but thats only because i can't increase the voltage due to my mobo.

I built my sons a pc based around a 3000+ and that happily clocked from 2 to 2.4ghz and still had more to go. 2.4 was what i settled at and it runs at that all the time.

bfar · 12 Oct 2006 at 14:47

pastymuncher said:
There's absolutely nothing wrong with the 754 socket in itself. Just check my siggy for proof. It's just that the 3400 Claw does'nt seem to be a very good clocker. Maybe it's a voltage thing, i just don't know. The DTR's depend mostly on the mobo.

My 3700+ Claw will max out at 2.795ghz but thats only because i can't increase the voltage due to my mobo.

I built my sons a pc based around a 3000+ and that happily clocked from 2 to 2.4ghz and still had more to go. 2.4 was what i settled at and it runs at that all the time.

I'm in the same boat - the mobo won't allow me to change the voltage. There's an option there, but it has no effect.

Its annoying, because i could reach 2.4 easily on my old mobo - and that was without pci locks.