SPCR

Does anybody know? I have a brand new one that I have been saving for the 4870, which still may be the card I buy. Perhaps it is too soon to know if it will fit the 4890.

Yes, it will fit just fine. The hole pattern is exactly the same as the HD4870...

Thanks. I was wondering the same thing.

You only have to worry about the VRM cooling, Mosfets mostly.
But since there are more phases than on the 4870, it shouldn't be as difficult.

Phases? How much of a difference does it make?

How about the T-Rad^2 (for those who can't fit the Accelero)?

I emailed Thermalright support, and they say that they're not saying that it fits for now, and they are working on a solution for the HD4890... I'm not sure that's entirely accurate. If it fits the HD4870, it should surely fit the HD4890, given that one has some extra RAMsinks, just in case?

If it fits the HD4870, it will fit the HD4890 (current reference designs).

This includes the Accelero S1, Accelero Twin Turbo, T-Rad^2, HR-03GT, Musashi, Battleaxe, etc.

Obviously full waterblocks do not apply though. They will need to be redesigned for the HD4890.

The VRMs on the HD4890 should be easier to cool, since there are more of them. Increased surface area and extra phases means the heat is distributed in a more even fashion and can be removed with greater efficiency. This speculation remains to be seen, though.

Heatsinks for the memory shouldn't be a problem, as the HD4890 has 8 chips, just like the HD4870 (not including the 2GB models)...

Thanks for the info people.

Tzupy wrote:You only have to worry about the VRM cooling, Mosfets mostly.
But since there are more phases than on the 4870, it shouldn't be as difficult.

How do I identify the MOSFETS? I know I could google this, but I really don't have a lot of time to kill today.

I have installed 3rd party coolers on a few cards, but never knew I had to cool anything other than the GPU and RAM.

Here's a shot of a reference HD4890, with it's heatsink/fan removed.



The areas marked in green are the VRM chips that need heatsinks applied along with active cooling...

Okay, thanks a lot.

nafets kept beating me on reply time, and had accurate answers, I didn't have much to add.
Just to clarify the matter: the chips market with green are Mosfets, they can get quite hot. Since they are small, they need heatsinks and airflow.
The larger ones to their left are inductors, they may get a bit hot too, but usually nothing to worry about (maybe they catch the heat off the Mosfets).
What makes the Mosfets of the 4870 run very hot is that there are only 3, not 5 like on this 4890 PCB, so the load is ~50% higher / chip.

Great info in this thread. Thanks all!

IF/when you buy a card let us know how it goes.

I've ordered an Asus 4890 and will transfer the Accelero S1 rev2 from my current card to it before overclocking and overvolting if needed. I'm aware of the VRM issue, and will use the VRM sink that came with the Accelero and any other heatsinks if needed. Looking forward to it!

OK, Asus Top 4890 has just arrived. Will whack the S1 on when I get home from work.

Right, S1 fitted. To be honest it has been a right pain. However, it is much, much quieter than the stock cooler.

The main issue has been cooling the VRMs. My current solution is the Accelero VRM heatsink with the screw hole pieces hacksawed off. This heatsink is then attached to the VRMs with double sided thermal tape and a rubber band. This is very much a temporary solution until I can find a better VRM cooler, as I'm not sure at what temperature the rubber band will melt! Desktop temperatures are 44 degrees for the core and 54 degrees for the VRMs. I've not yet loaded the card, apart from an aborted attempt when the VRM heatsink was not secured with the rubber band, fell off, and the VRMs hit 113 degrees!

Idle power consumption is almost 40W higher than with my 3870. However, dropping the RAM speed to 500Mhz QDR compared to the 1000Mhz QDR stock speed saves 20W! I will manually set the RAM speed on an ongoing basis.

I’m still waiting for the VRM cooling solution Thermalright unveiled at Computex.

VRM cooler

Yep , that does look like the best option out there when it is eventually released. Zalman also have a solution, but it is no way near in sophistication and I don't think it would be compatible with an Accelero:

http://www.techpowerup.com/97201/Zalman ... _4870.html

Zalmans solution looks way, way to “weakâ€

The Thermalright VRM cooler can't come soon enough. I tried disposing of the rubber band to fit some zip ties, but because the VRMs are so small, the VRM heatsink was knocked out of balance and wasn't making good contact. The rubber band remains...

However, I have disposed of the Arctic Cooling Turbo Module for an Antec Tricool fan that is now zip tied to the Accelero. Desktop GPU temperature is now 6 degrees lower, as are the VRM temps. The noise level is actually lower too, as the Turbo Module had started to whine.

roadie wrote:The Thermalright VRM cooler can't come soon enough.

Do not despair brother roadie, have a looksee here... our prayers to the cooling gods appears to have been answered, at last!

They look good! However, I have just received a Zalman ZM-RHS90:

http://www.zalman.co.kr/ENG/product/Pro ... sp?idx=352

I'm not 100% as to whether it will fit in conjunction with the Accelero, but I'll give it a go next week, as I am away for the weekend.

If it doesn't then I will certainly get the most suitable Thermalright when it becomes available.

If you got the Zalman to fit how is it working for you?

Tried fitting the Zalman tonight. It didn't fit with the Accelero. Would have to cut the fins down with a hacksaw in order to get it to fit. Even with bending the Accelero, some modification to the VRM heatsink would be necessary.

Thank's for letting me know roadie and to bad it didnt fit, also, what would be required to make it fit is just a bit much I say.

double post...

double post

The Accelero S1 DOES fit with the Zalman VRM heatsink with modification. The main problem is that the right side heatpipe hits the Zalman heatsink - so you need to machine a groove down the length of the Zalman.

I think the heatpipes are about 4mm, so the groove that I cut is maybe 3-4mm deep and 7-10mm wide. Picture the Zalman as the hotdog bun, and the heatpipe as the hotdog. I used a dremel tool with an "engraving cutter" and small (~4mm?) sanding drums (it's all I had available). If you use this method, you'll probably need 5 or more drums to finish the job, since they grind themselves down to nothing very quickly. Silica grinding wheels are useless on aluminum.

I also removed the lower two fins on the Zalman (both partial fins).

Once this is done, the fins on the Accelero mesh with the fins on the Zalman, and the heatsink can be seated properly on the GPU.

MSI 4890 OC
Accelero S1 rev2
Zalman ZM-RHS90

Nice, good news!
Would you be able to post some pics?