ATI 4850/4870 voltmod thread

[dejanh]

Here we go gents (and maybe some ladies)...time to stir up some s***

I've been posting for weeks now how it looks like there are major issues with 4870 VRM cooling and/or the overall power design...some listened, some did not...

Finally, here is some official confirmation of VRM issues...sadly ATI just "glazes" over this by hacking the driver and not fixing a problem...

http://en.expreview.com/2008/08/26/a...it-run-slower/

Now again, I will care to reiterate over all of the threads that I have been posting in related to this...

This thread is a pretty good collection of all the places I have posted about this already (see first post)... http://forums.tweaktown.com/f31/diam...edition-27348/

Let's hear some opinions!

[G H Z]

I have three of these cards and don't experience any of the problems you have have. Furthermore ATI Tool is not current software, W1zzard himself has said you cannot use it for current gen card testing so that part of your 'info' isn't valid.

[xMrBunglex]

Dejanh, don't spam the entire forum with that same post. pick one thread and leave it there.

[96redformula]

Thanks so much for your help guys. I got my 4850 at the point I wanted it at. I will have to push it to the limits when the time comes, right now no need as I don't play crysis any more and max resolution 1920x1080.

850/1125 - Not maximum, but daily clocks
1.4V Hardmod (It took me about 45 minutes, I know I am a hard mod rookie.)

[xMrBunglex]

good stuff. your 4850 clocks higher than my unmodded 4870's

[Barr3l Rid3r]

good stuff. your 4850 clocks higher than my unmodded 4870's

And it works in furmark also

[96redformula]

And it works in furmark also

So True

[DemonEyez]

Here we go gents (and maybe some ladies)...time to stir up some s***

I've been posting for weeks now how it looks like there are major issues with 4870 VRM cooling and/or the overall power design...some listened, some did not...

Finally, here is some official confirmation of VRM issues...sadly ATI just "glazes" over this by hacking the driver and not fixing a problem...

http://en.expreview.com/2008/08/26/a...it-run-slower/

Now again, I will care to reiterate over all of the threads that I have been posting in related to this...

This thread is a pretty good collection of all the places I have posted about this already (see first post)... http://forums.tweaktown.com/f31/diam...edition-27348/

Let's hear some opinions!

Enough already.... It's clear that you're not happy with Ati's HD4870 , but man, please stop spamming you opinion about Ati in this and other forums. You're just bashing them and that has nothing to with overclocking or voltmodding in this case.
We all know how you feel about Ati's 'vrm problems' (how could we not, after so many posts )
If you're so unhappy with them, sell your card get a NVidia card and send you rants at them directly by mail or by phone , i don't care. But stop posting this nonsense here. Now back on-topic....pleaseee

[h3x0r_1984]

Most of the people here are gonna take off the stock cooling on the HD4870,and heating the VRM won't be a problem.And we're gonna mod it too..

Who gives a crap that on stock cooler u have artifacts with some Diamond Black edition junk.... ?

[Barr3l Rid3r]

Most of the people here are gonna take off the stock cooling on the HD4870,and heating the VRM won't be a problem.And we're gonna mod it too..

Who gives a crap that on stock cooler u have artifacts with some Diamond Black edition junk.... ?

It follows the reference design... so it shouldn't happen only w/ diamond.
Anyway, even u got better cooling u won't made the VRM stronger, and that's the point, u will still having to choose if u wanna clock the gpu or the memory, u still worried that u got a weak overloaded noisy digital VRM w/ only 3 phases...

Exception to the new Gainward Goldensample 4870, it have the same analog 4 phases vrm as the 4850 but w/ better and bigger ferrite chokes and mosfets, better and all solids capacitors, 8pin PCI-e conector and a plus of DDR5.

[dejanh]

Dejanh, don't spam the entire forum with that same post. pick one thread and leave it there.

Sorry, I got carried away when I saw that somebody actually brought this thing to light in a more official manner

It follows the reference design... so it shouldn't happen only w/ diamond.
Anyway, even u got better cooling u won't made the VRM stronger, and that's the point, u will still having to choose if u wanna clock the gpu or the memory, u still worried that u got a weak overloaded noisy digital VRM w/ only 3 phases...

Exception to the new Gainward Goldensample 4870, it have the same analog 4 phases vrm as the 4850 but w/ better and bigger ferrite chokes and mosfets, better and all solids capacitors, 8pin PCI-e conector and a plus of DDR5.

Thank you Barr3l. Clearly some of these guys do not get the point at all...not my problem I guess. Thanks

Speaking of which, the details of the Gainward card look promising for the Palit Sonic Dual Edition as it seems to be the same card Can't wait to see how high I can push this one. The XOC BE capped out at about 860/1160 with maximum stable voltage of about 1.35-1.37V. Not much gain considering the card is voltmodded

Edit: Oh yeah, looks like the Palit card is the same as the Gainward. A review is up, it's in Thai but at least you can see the card nicely. No more digital VRMs baby! The custom designed sink looks sweet too, full coverage of the PCB, front to back See here...

http://www.unlimitpc.com/index.php?n...pid=111&page=1

[Barr3l Rid3r]

Sorry, I got carried away when I saw that somebody actually brought this thing to light in a more official manner



Thank you Barr3l. Clearly some of these guys do not get the point at all...not my problem I guess. Thanks

Speaking of which, the details of the Gainward card look promising for the Palit Sonic Dual Edition as it seems to be the same card Can't wait to see how high I can push this one. The XOC BE capped out at about 860/1160 with maximum stable voltage of about 1.35-1.37V. Not much gain considering the card is voltmodded

Edit: Oh yeah, looks like the Palit card is the same as the Gainward. A review is up, it's in Thai but at least you can see the card nicely. No more digital VRMs baby! The custom designed sink looks sweet too, full coverage of the PCB, front to back See here...

http://www.unlimitpc.com/index.php?n...pid=111&page=1

woow it sux heavily, vmodded 4870 and only 860Mhz? w/ 1.42V i can hit 920Mhz in my air cooled 4850...

[dejanh]

woow it sux heavily, vmodded 4870 and only 860Mhz? w/ 1.42V i can hit 920Mhz in my air cooled 4850...

Yeah, you can't get the 4870 that high. You can't even get the voltage that high. Peak core is 1.35V - 1.37V. At least that seems to be the consensus to date. Nobody reported being able to go higher and stay stable. Even at those volts it is a juggling act between your core volts and memory volts. It really seems the 4850s have a superior power design to the 4870s. I can't wait to try that new sonic dual edition 4870 with a different power design

[xMrBunglex]

i think it's just that the 4850 uses GDDR3, which uses a lot less energy and creates less heat.

[dejanh]

i think it's just that the 4850 uses GDDR3, which uses a lot less energy and creates less heat.

I did not verify this, but is GDDR5 not supposed to have an advantage of requiring less power and being cooler running when compared to GDDR3/4? The stock voltage is 1.501V too which is quite low and sort of supports this claim...

[xMrBunglex]

I did not verify this, but is GDDR5 not supposed to have an advantage of requiring less power and being cooler running when compared to GDDR3/4? The stock voltage is 1.501V too which is quite low and sort of supports this claim...

i don't know for sure. i know it uses less energy if it's clocked at the same speed, but the GDDR5 runs twice as fast.

[Oese]

that makes sense. indeed, clockspeed is about the same (900mhz) but it has to push double the data. so this MUST consume energy due to the laws of thermodynamics..

[h3x0r_1984]

that makes sense. indeed, clockspeed is about the same (900mhz) but it has to push double the data. so this MUST consume energy due to the laws of thermodynamics..

Of course it makes no sense at all...does DDR2 consume more power than the DDR? No.

Without voldmodding the memory on the 4870..would u get to a 900 with 1.4V ?

[dejanh]

i don't know for sure. i know it uses less energy if it's clocked at the same speed, but the GDDR5 runs twice as fast.

Well, actually I am pretty sure I am right. The memory runs at 1.5V and power consumption (W) is directly related to the supply voltage through amperage (A) so I'd say its power consumption is certainly lower than that of GDDR3/4. This is also supported by information provided by Qimonda in their spec and data sheets, as well as through information available online based on AMD's comments one of which can be found here...

http://www.allbusiness.com/electroni...1412683-1.html

[xMrBunglex]

there has to be a reason for the 4870's beefy VRM's though. i doubt it's because of its modest core clock speed advantage.

[dejanh]

there has to be a reason for the 4870's beefy VRM's though. i doubt it's because of its modest core clock speed advantage.

I think its rather a lack of beefy VRMs. I have a feeling they cheaped out on the voltage controllers on the 4870. The PCB even has one empty slot for a fourth VRM to feed the GPU but it is unused. 3 phase power + 3 phase inductor for the GPU, 2 and 2 for the memory. It's the GPU asking for a lot of juice when you are running at or near 100% GPU utlization that causes the VRMs to overheat, at least that is my obervation to date and it's supported even by thermal images taken to date on the card (http://www.forumdeluxx.de/forum/show...93#post9575293). The memory VRMs get very hot too, for which I have no explanation other than the GPU VRMs cause the memory VRMs to heat up more because of proximity.

Also, the surface area of the VRMs is so damn tiny it is very difficult to cool them efficiently. All the heat gets concentrated on such a small area...

[exhausted mule]

where do you guys buy all your vr's for these?

[EightyDuce]

where do you guys buy all your vr's for these?

Digikey or Mouser, these two have a huge inventory and shipment is fast.

[exhausted mule]

excellent. ty

[dnottis]

I flashed my Asus HD4870 with the Asus TOP bios. Runs 850 core 24/7 but no problems up to 890Mhz (highest the ASUS TOP allows) core stock, no vmods done at all.

Cooled with MP-01 and some VRM sinks with a 120mm blowing over them.

Here was a run at 850 mhz,