Swiftech Releases Komodo HD5800 F/C Waterblock For ATI

[dejanh]

sorry for not being able to get back to you faster, but I am in China right now, and facing very hectic schedule.

You are essentially correct: the key here is standoff height. So please make sure that all standoffs are completly fastened tight, particularly in the VRM's area. One or two more turns of fastening the standoff will make the difference between poor contact and good contact. We are indeed dealing with very small distances here, of the order of 0.1 to 0.2mm. anmd since we do not want to warp the PCB in excess, tolerances are tight indeed.

I officially implemented the "no pad" tweak after successfully testing it myself with 5850, 5870 and 5970, so I felt very comfortable recommending it.

BUT making sure that all standoffs are fastened tight is something that I do automatically without even thinking twice about it, and in hindsight I should have added this in the instructions. Using pads gave us sufficient margin to allow for larger tolerance gaps, but not using pads is obviously reducing the margin of tolerance that we have, and therefore absolute repect of the specified standoff height relative to PCB becomes obviously critical.

The conendrum we find ourselves into is this: using standoffs to prevent excessive warpage of the PCB, in other words user safety, and the desire to provide a perfect TIM between VRM's and copper plate. In theory, these two goals are mutually incompatible. In practice, they are possible, but reserved to advanced users who have a solid understanding of the underlying difficulties associated with this kind of mechanical challenge. This is the very reason why I included the tweak in an "advanced users" section of the installation guide.

Other vendors (who do not use standoffs) do provide a better TIM, but this is at the cost of safety. The users of these competing solutions typically qualify themselves as advanced, and so they do not really mind taking the risk. We on the other hand, want to provide safety as well as performance, and it would appear that we still have either some tweaking or better maybe explaining to do in order to accomplish this.

Doing a hard mount (without pads) is quite possible with the Komodo's, I have done it, and I'll stick to my guns about it. Performance is exceptional, and pcb warpage was minimal. Should I revise my standoff heights and therefore reduce the tolerance gap without pads is something I now need to consider carefully.

Hi Gabe, thanks for taking the time to quickly reply. Unfortunately I have automatically done exactly what you have suggested. All of the observations and measurements that I have provided have been taken after tightening the standoffs as much as physically possible on the whole block, and as I have indicated previously, even replacing "longer" standoffs for "shorter" standoffs in critical areas by swapping around standoffs on the block. There is simply no way to make the VRM contact the plateau with paste. Furthermore, maximum compression of the block to the card was done in that there were no gaps at all between any standoff and the PCB, or simply put the card was as flush to the Komodo block as it can physically get.

I agree completely that you should try to revisit the standoff heights to lower the tolerance gap without pads. As it is now you have a fair amount of tolerance, at least in my testing. Furthermore, I would ensure that the machining height deviation tolerances on standoffs and VRM plateau areas be virtually eliminated as not doing so results in potential problems with contact due to the fine measurements we are dealing with here. Basically, you should strive to have all standoffs be the exact or as close to exact height that they need to be as possible as well as ensuring even and correct height of the VRM cooling plateaus of each block.

I am waiting for the RMA MSI R5850 to come back as well was for an Asus EAH5850 card to arrive. I will repeat my testing with those cards as well to ensure that this was not just a rare occurrence with some MSI R5850 cards. However, having said that this should not be taken as a reason to not address this at all. I realize that you have successfully tested this method in house, but both you and I know that not all cards will be identical with identical heights and to recommend a blanket method based on a gross assumption that it would work in every case is unrealistic at best. Even with reduced tolerances there should be a notice indicating that the performance may not be as desired.

Finally, one option that you do have is to include some longer fasteners that could be used to mount the block without standoffs and indicate that this is considered advanced installation with higher risk of damaging the card but would still leave the option for those people who may want to mount the whole block without pads and standoffs to do so. After all, in terms of its thermal design Komodo is really a great block and can pretty well be a top performer if it were not for a few of these issues.

It is imperative as you already know to be extremely careful here, no matter which path is chosen, as crushing digital VRMs is very easy to do and that's the last thing you want people to do after trying to get better temperatures out of their VRMs.

Hello,

The indention you have marked, "Bad contact, no compression" with a red line with two arrows on each end, can you remove the pad sitting inside that indention to give your block more height/clearance to successfully cover the components on the pcb marked by the white sticker, "CPL2-3". Then you may have greater compression/pressure on the 5 VT1165 slaves to the left which are not being touched by your cooling block. Also, can you make your cooling block mount tighter to that area of vrm slaves?

Why not use a highly conductive thick thermal pad of good quality to mount on those 5 components. These 5 slaves need *MUCH* more cooling than the parts under the white sticker CPL2-3, which require little cooling, and are not even touching the stock cooler.

I think you misunderstood what the issue here is actually. Komodo has no problem contacting the VRMs with the stock pad or with any other pad thicker than (I believe) about 0.3mm-0.5mm. However, as of recently Swiftech has revised their mounting instructions to include an advanced step that involves removing the thermal pads from the VRM cooling areas and replacing the same with paste for better thermal interface. However, unlike in Swiftech testing, I have not found it possible to use this method with at least one HD 5850 and two Komodo blocks as the dimensions of the standoffs do not allow for proper contact to be made between the block and the card even if fully compressed.

In terms of removing pads to give more clearance, I have already responded to this earlier, and then Gabe responded to it as well. The clearance on Komodo is not controlled by pads, it is controlled by standoffs. The only way to make the block more flush to the card is to use smaller standoffs or to file down the existing ones, both of which requires a physical change to the current design.