Project 8600GTX

[bartx]

Hello,

I had a simple plan. Connect working VRM from 8800GTX (bcoz all Evga stuff is too expensive for me) to 8600GT and make some scores. I bought dead 8800GTX and working 8600GT Sonic + and connected external VRM. There are quite a lot of modifications:

- vgpu mod, tested range is 1.3-1.9v
- vmem regulation, tested range 1.5v-2.5v
- connected vsense pins (when cutting the pcb, these connections where cutted too), it provides much more stable voltage
- one 3300uf capacitor soldered on 8600GT board, probably no gain


Pictures of the card:










Voltages are really stable, fluctuation of vmem is around 0.003v, on vgpu 0.02v. Vdrop is small to - 0.05V. I know that I don't have many wires, and they're too long, but I don't think it'll make a noticeable difference in clocks. I'd get more gain changing cooling to at least a decent single stage.

Card was cooled waterchiller (MCW60 block), coolant has temperature around -28C, vgpu ~1.75V, vmem 2.03V. 1067Mhz @ Core is one of the best clocks in the world made on this card, so I'm really happy with it It was done around 3 months ago, but still most of my scores are placed high on Hwbot.

http://hwbot.org/submission/2316031_...r3_77431_marks

http://hwbot.org/submission/2316027_...r3_30552_marks

http://hwbot.org/submission/2316029_...r3_19668_marks

http://hwbot.org/submission/2316034_...3_278404_marks

http://hwbot.org/submission/2316028_...r3_10329_marks

I still had this card in working condition, so I'll made round two some day, this time with better cpu and cooling.

Best regards

[Stelios]

Nice stuff ! Just love this kind of o/c !!

[Mafio]

awesome modding skill.
congrats.

[Ivanlabrie]

Very nice work!
I gotta do stuff like this...what's next? Using a 3770k and a z77 board?

[stangracin3]

I miss my 8600GT's those things were beast to me back in the day. of course i was coming from a ati radeon 9250 ROFL

EDIT:
found my old post. I think i ended up getting it to 810 on the core. this was on the stock air cooling with the shroud removed and 120's surrounding it

http://www.xtremesystems.org/forums/...-GT&highlight=
get a second and do sli now lol

[Ryleh]

Oh man, this is absolutely absurd! Very impressive!

[K404]

....and there was me thinking the 8800GTX/ Ultra PWM was complete crap.

VERY nice work bro!!!

[TiN_]

I'd suggest soldering ground wires closer to GPU.
Also putting some 0805/0603 MLCCs and POSCAPs right behind GPU could give you 25-50MHz too.
Usual rule - more capacitance is better when it's close to point of load, not somewhere in another galaxy at PCB corner.

Cheers.

[dernettemann]

Very nice work

[bartx]

I'd suggest soldering ground wires closer to GPU.
Also putting some 0805/0603 MLCCs and POSCAPs right behind GPU could give you 25-50MHz too.
Usual rule - more capacitance is better when it's close to point of load, not somewhere in another galaxy at PCB corner.
Cheers.

Thanks for the tips But in my opinion better cooling is the way to go. 8600GT core is so small, I had positive temperatures in load. I've noticed, that shader clock scales very well with temperature and around these frequencies it has the biggest influence on scores. Also better cpu woulnd't hurt too.

[K404]

I hope you removed that plastic shim around the core before benching Every time I get a card with one of those, I remove it and I get up to 15 degrees lower temps.

[bassplayer]

I hope you removed that plastic shim around the core before benching Every time I get a card with one of those, I remove it and I get up to 15 degrees lower temps.

Every time I get a card without one of those, I crush the core