Stren's Titan Water Block Roundup

[stren]

Interesting flow behavior on the Koolance. Perhaps there is some block expansion happening as flow and internal pressure increases causing that. I know I have seen some odd things in pressure drop curves flattening out like the GTX radiator series that was presumably due to the very thin tubes expanding under pressure.

Love the work and think the one mount concept first is very wise. Take care of that card and take your time. Enjoy the Vaca.. much deserved break!!

Thanks Martin - interesting - yes it reminded me of a laminar to turbulent transition plot from back in the day. But I thought we always had turbulent flow these days so your explanation might be better!

stren
>...but I have those temps on the AquaComputer block that I'm running now. Yeah we'll see about the VRM's. I'm measuring about 50C over ambient on the VRM's right now with the AC block.
+50C from ambient directly on one of the transistors? And I guess it at stock clocks (with boost only)? I think it's a good idea to use a backplate with pads (need to pick up thickness) for VRM zone + slow fan for cooling that backplate. Did it with GTX 580s and will repeat with Titans.

+50C above ambient measured on the back of the board underneath where the VRMs are. This was the worst spot of the 6 phases, others were cooler. This raised to ~57C at very low flow. This is without TIM on the thermal pads though so I bet it could be improved.

>I think adding MX2 to both sides of the thermal pad really helps (which this run doesn't have), but I need to get firm data on that to be honest.
EK wrote about this in manual. But is that OK if I have MX3? And is there any benefit? If it's only 1-2-3 degrees...

Any non conductive TIM should be fine. I don't have a definitive numerical answer for you, but the EK block (where I did use TIM on the vram pads) was about 15C better on the VRAM chips on the back of the card than the AC block (where I didn't use TIM on the pads). Now that could be block differences but it might be the TIM.

>[i]I also noted that a thermal pad on the VRM sense resistor really helps to stabilize the card's power measurements over temperature. That resistor does not have a zero temp co and could be causing people to power limit unnecessarily./i]
Sorry, I don`t understand - resistor on Titan`s PCB?
I only OC`ed this card under air (stock) in open case, fan was at 5000+ RPM and + two 120 mm side Slip Streams (1600 and 1900 RPM). Card consumption was up to 330W and back side of PCB (on the opposite side of VRM) was about 65-70C (infrared thermometer). Ambient ~24C.

There is a resistor (or at least I assume it's a resistor) for each phase next to the regulator labelled R22. I assume this means it's a high power 0.22 ohm resistor used to measure the output current of the regulator. But this is a guess. Most instructions tell you to not put a thermal pad on it, but when I didn't on the Koolance block the power measurements were very sensitive to block temperature and would raise 5% over the test. Given that with a stock bios you can easily hit the power limit when overclocking then adding a thermal pad to that resistor might help extend your ability to overclock it.

naennon
>do NOT use pads on vram chips
block will not get enough contact to the gpu
But according Koolance manual, we must use them. That's strange. But also they wrote:

Multiple types of heat transfer pads are included with some Koolance blocks.
You might not require both (check the pad diagram). This is done because card
manufactures change the component height tolerance from time to time.

But it looks confusing, I prefer EK way

Yeah I saw this yesterday too (I didn't have a manual shipped with the block as it was shipped so quickly). So they kind of agree except Koolance should have specified that you may not even have to use a pad at all if the spread is still too thick.

Compiled the AquaComputer GPU core results - it's a bunch more restrictive as we knew from the earlier plots. In a single CPU, GPU, Rad, 4xQDC loop it could drop flow from ~1.05GPM (for EK and Koolance) to 0.85GPM. At higher flows it does about the same as the EK block, however at lower flows it does better. Between the two I'd recommend the AC for multiple cards in parallel and the EK for a single card, or cards in series.

Note the lowest pump setting for the AC block is off the scale of my flow meter. The float was not pegged so I made an estimate of 0.28GPM, but this number will be far from exact.



That's about all I'll have time for before I leave for vacation. I'll be back by the end of the month and will run the XSPC and then the EVGA. Hopefully the other blocks will arrive shortly after I get back.