4870 Accelero Twin Turbo fails!

[TimTheEnchanter]

Tried to bump my last thread but didn't get any attention... so here:

Finally got my Accelero twin turbo to cool and mostly make my 4870 quiet.

Worked perfectly... until i found out that my VRM get way too hot. I installed the heatsinks correctly... just... way too hot. Over 140 degrees. The GPU ain't that bad, though, still a little hot.

I've seen this thread where there seems to be the same problem :

ATI 4870: AC Twin Turbo vs. Scythe "Musashi" - [H]ard|Forum

For those who do not want to read, here's his solution : put back the stock cooling plate (with of course removed stock heatsink/fan) and add the accelero on it. He had excellent results.

What do you guys think, is it my only solution?

Second problem : couldn't modify the fan speed, but it's no big deal.

[TimTheEnchanter]

Still nothing to say? that surprises me from the HWC community... whether the air cooling forum isnt't popular, or people don't know what to say or haven't been active lately...

You guys know any other heatsinks or thermal tape/paste i could get to fix the problem?

[bojangles]

Can you get smaller copper heatsinks under there? And are you sure those temps are actually for real? I would test with an infrared temperature sensor.

[TimTheEnchanter]

Being not the only one having this issue and having my computer crash while running furmark, i am pretty sure those temps are real. It is possible to get smaller or low profiles heatsink under there, problem is i do not know which ones are worth it.

[Eagle Eye]

Tim,

Can you please rerun your test during normal operation, for example while gaming. If your temps reach the same you might have an argument, however as it stand furmark stresses components beyond what is considered "normal" Its exactly why manufacturers will not improve on something that isn't absolutely necessary.

Regards,

EE

[TimTheEnchanter]

Hum true, but i've already done it before posting this thread. While gaming, using gpu-z, the vddc slave 1,2 and 3 (all of them) reach an average of 120 degres, which does not cause any crash but is still to high.

[JD]

Not sure if this will solve it but at least it's a solid piece of aluminum and uses push pins so it would at least make better contact. Plus you could use some MX-2 paste instead of that thermal tape.

Zalman ZM-RHS70 VGA Cooler for FET's on ATI Radeon HD4870/4850 Graphics cards Products Model: ZM-RHS70 [ZM-RHS70] : Performance-PCs.com, ... sleeve it and they will come

[TimTheEnchanter]

Did some research and it says that these zalman heatsinks are too tall for my accelero. I need low profile heatsinks. Honestly, the only solution i see is the stock plate trick, but i have no thermal tape, only thermal grease... i couldn't place my accelero back on, and the vrm wouldn't transfer the heat properly...

[MpG]

You need something on the VRM's for certain, as the stock solution just isn't robust enough to survive without. It's a well-established problem with the 4870's, but since it works, no OEM is going to bother changing it. I'm not familiar with the stock plate, but the Zalman unit that JD linked to looked pretty decent, as long as there's clearance. Most VRM's these days are rated to 150 degrees, so as long as you've got some sort of metal on them, I can't see you having any issues.

Edit: No clearance for the Zalman unit? Under those circumstances, I'd either 1) get some thermal epoxy to stick the sink on, or 2) use grease, but use some dabs of hot glue to hold the sinks against the VRM's. Option 1 is preferable, but I have done option 2 on motherboard VRM's before, and as long as you do it right, it actually works quite well.

[TimTheEnchanter]

Thanks MpG. Can you make it clearer for me when you talk about thermal epoxy? May be my lack of english understanding, but i don't undertsand and google doesn't help much.