8800GT voltage mods

[babalouj]

Well I put the 77X resistors on there, did the correct OCP mod, then adjusted the vmem to 1.86V and vgpu to 1.4V. I gained 30mhz core, 0 mhz shader, and 50mhz memory bringing me to 880/2100/2100 @ 57C loaded. Not too shabby for a free mod.

[jason4207]

Has anyone had trouble overclocking their memory to previous stable levels after the gpu volt mod? My memory could do 1000 before, now I'm having trouble with it @ 975. I think maybe my core hates 800mhz even if I pump the voltage beyong 1.3v. It seems stable if the memory is left at 950 though. I have Hynix chips (HY5RS123235B) which are rated to do 1000. Stock memory voltage is 2.00v. Any thoughts?

Also, what are the symptoms of OVP kicking in?

Yes. I was stable at 1026 before modding, and after doing the vmem buck I was stable at 1056. After I cranked up the vcore I had to dial the memory back down to 1044.

Well I put the 77X resistors on there, did the correct OCP mod, then adjusted the vmem to 1.86V and vgpu to 1.4V. I gained 30mhz core, 0 mhz shader, and 50mhz memory bringing me to 880/2100/2100 @ 57C loaded. Not too shabby for a free mod.

I wasn't sure if the 77X would work right, but like you said it's only 2%...it can't mess it up that bad. Glad you got it working!

[nvrmind]

Do you think it's just the Quimonda chips that are benefiting from the vmem buck mod or Samsung and Hynix as well? I guess I could try pencil modding the memory to see if it responds to higher voltage and if not I could try the vmem buck mod. Kind of annoys me I'm losing like 50 mhz on the memory.

[natedog420]

ok well i dont have the resistors i took off for the ocp mod i ended up losing them. i have an old motherboard. what do i need to measure to find new ones. can i just solder in one of the new ones since the stock ones are gone? i run 1.45 volts usually so i need the 1.2k like you say.

[nvrmind]

Its odd, I've been up to 1.45v on my MSI with no indication of the OVP activating. Doesn't seem to matter as my card won't clock any higher after 1.29v. What voltages are considered unsafe on these cards?

[jason4207]

Do you think it's just the Quimonda chips that are benefiting from the vmem buck mod or Samsung and Hynix as well? I guess I could try pencil modding the memory to see if it responds to higher voltage and if not I could try the vmem buck mod. Kind of annoys me I'm losing like 50 mhz on the memory.

I have no idea about the Samsung or Hynix. I've been waiting for someone to post something. Your card is behaving like mine, though, so my 1st guess would be that vmem buck would help you. No way to know unless you try!

ok well i dont have the resistors i took off for the ocp mod i ended up losing them. i have an old motherboard. what do i need to measure to find new ones. can i just solder in one of the new ones since the stock ones are gone? i run 1.45 volts usually so i need the 1.2k like you say.

They are 78X. If you see SMR's on your MoBo w/ the same label they might work. If not maybe you can find them online. Only way to measure resistors on the Mobo is to remove them first.

You don't need 1.2k for 1.45v. 3.8-4.2k would work fine for that. You shouldn't have any issues until ~1.625v idle w/ 3.8-4.2k.

Its odd, I've been up to 1.45v on my MSI with no indication of the [s]OVP[/s] OCP activating. Doesn't seem to matter as my card won't clock any higher after 1.29v. What voltages are considered unsafe on these cards?

Have you tried running AquaMark3? That seems to be a good stress test for OCP.

[nvrmind]

I haven't tried AquaMark3. OVP doesn't seem to matter in my case since my card won't respond to higher than 1.29v. I was hoping to get the shader to around 2000, but 1825 seems to be it's limit. My card is one of the lower clocking cards I've seen on here. The voltage mod got me 90mhz on the core and 50 on the shader (800/1825). Not too bad, but I was hoping for more. Now if I can just figure out this memory issue.

I'll try the pencil mod first with these Hynix chips. If increasing mem voltage doesn't help, than I guess I'll go ahead with the vmem buck mod. I measured the voltage around 1.9v+.