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(cf)Eclipse
Freelance Overclocker
- Joined
- Feb 18, 2003
- Messages
- 30,027
so, i needed to pick up a video card to replace my somewhat weak gf4mx.. 
looked around. got a refurb x800pro. ended up being DOA, so scatch that plan. looked some more, decided that i'd pay the money for a 7600gt, the MSI one with a big heatsink:
http://www.newegg.com/Product/Product.asp?Item=N82E16814127209
i figured it looks like it cools the ram, and should have no problem dissipating a lot of heat. always a good thing in my eyes.
when it showed up, i took some pics:
not a bad packaging method. a little bit on the wasteful side though...
the underside of the card
after a bit of testing to make sure it works at stock clocks, i went and had a look at the heatsink more carefully. i noticed when i pulled it out of the box that the ram wasn't contacting the thermal strips. definitely a big no-no. sadly, the best thing that it seems i can do until i switch over to my maze4 and ramsinks is just put a big blob of ceramique in
top of the card and bottom of the heatsink. notice how thick that thermal tape is... it scares me, i doubt the ram gets very good cooling at all, especially with the ceramique in place.
the memory chips are 512mbit infineon, 1.4ns binned.
here's what the heatsink looks like without the plastic cover on.
thus, my overclocking adventure begins.. and ended VERY quickly when i found out that the maximum core mhz the card would do was around 610mhz.. 30mhz over stock. brought my 3dmark05 score up from ~6.35k to 6.55k. definitly a letdown, so i'll have to find a way around that. keep in mind that this is not a reference pcb, so i had to do a bit of poking about and asking questions to find out what to do to the card to mod the core voltage.
in the meantime, i messed with the ram. i think i just have good luck with memory or something. ram made it up for ~860mhz benchable from 750mhz stock... and this is with a huge blob of ceramique keeping it cool. this was a bit better boost on performance, bringing it up to 6.75k from 6.35k at stock.
finally, i was pointed in the right direction for a vcore mod. this is the result
due to how the mod works, even with the VR turned all the way up to 20k ohms, the stock voltage has risen from 1.33v to 1.37v.
did some testing, voltage scaling is as follows:
1.33v = ~610mhz
1.37v = ~630mhz
1.400v = ~640mhz
1.425v = ~650mhz
1.450v = 659mhz
1.475v = 670mhz
1.500v = 678mhz
1.525v = 684mhz
1.550v = 695mhz
not too bad, roughly 10mhz per .025v with some inconsistancies here and there, should lead to a pretty nice performance gain.
and surprisingly, at 1.55v, the card still didn't get too hot, hitting ~55c in a ~20c room.
though, it seems that at higher core clocks, the ram wasn't quite able to do 860mhz anymore. presumably due to the extra power being drawn by the core and the extra load on the ram to feed it more data.
just for kicks, an amusing side effect:
and all was said and done:
not too bad to say the least. for now, i've still got a few things to get figured out:
1. memory timings. at stock mhz, i'm able to cut the latency basically in half. however, finding the optimal point between mhz and timings that gives best performance isn't easy.
2. VDDR mod. i know what to do, the one thing that's holding me back is the thought of feeding hot ic's more voltage. i think i'm gonna wait till the ram has better cooling to do that.
looked around. got a refurb x800pro. ended up being DOA, so scatch that plan. looked some more, decided that i'd pay the money for a 7600gt, the MSI one with a big heatsink:
http://www.newegg.com/Product/Product.asp?Item=N82E16814127209
i figured it looks like it cools the ram, and should have no problem dissipating a lot of heat. always a good thing in my eyes.
when it showed up, i took some pics:
not a bad packaging method. a little bit on the wasteful side though...
the underside of the card
after a bit of testing to make sure it works at stock clocks, i went and had a look at the heatsink more carefully. i noticed when i pulled it out of the box that the ram wasn't contacting the thermal strips. definitely a big no-no. sadly, the best thing that it seems i can do until i switch over to my maze4 and ramsinks is just put a big blob of ceramique in
top of the card and bottom of the heatsink. notice how thick that thermal tape is... it scares me, i doubt the ram gets very good cooling at all, especially with the ceramique in place.
the memory chips are 512mbit infineon, 1.4ns binned.
here's what the heatsink looks like without the plastic cover on.
thus, my overclocking adventure begins.. and ended VERY quickly when i found out that the maximum core mhz the card would do was around 610mhz.. 30mhz over stock. brought my 3dmark05 score up from ~6.35k to 6.55k. definitly a letdown, so i'll have to find a way around that. keep in mind that this is not a reference pcb, so i had to do a bit of poking about and asking questions to find out what to do to the card to mod the core voltage.
in the meantime, i messed with the ram. i think i just have good luck with memory or something. ram made it up for ~860mhz benchable from 750mhz stock... and this is with a huge blob of ceramique keeping it cool. this was a bit better boost on performance, bringing it up to 6.75k from 6.35k at stock.
finally, i was pointed in the right direction for a vcore mod. this is the result
due to how the mod works, even with the VR turned all the way up to 20k ohms, the stock voltage has risen from 1.33v to 1.37v.
did some testing, voltage scaling is as follows:
1.33v = ~610mhz
1.37v = ~630mhz
1.400v = ~640mhz
1.425v = ~650mhz
1.450v = 659mhz
1.475v = 670mhz
1.500v = 678mhz
1.525v = 684mhz
1.550v = 695mhz
not too bad, roughly 10mhz per .025v with some inconsistancies here and there, should lead to a pretty nice performance gain.
and surprisingly, at 1.55v, the card still didn't get too hot, hitting ~55c in a ~20c room.
though, it seems that at higher core clocks, the ram wasn't quite able to do 860mhz anymore. presumably due to the extra power being drawn by the core and the extra load on the ram to feed it more data.
just for kicks, an amusing side effect:
and all was said and done:
not too bad to say the least. for now, i've still got a few things to get figured out:
1. memory timings. at stock mhz, i'm able to cut the latency basically in half. however, finding the optimal point between mhz and timings that gives best performance isn't easy.
2. VDDR mod. i know what to do, the one thing that's holding me back is the thought of feeding hot ic's more voltage. i think i'm gonna wait till the ram has better cooling to do that.
