Laing D5 vario runs hotter than D4?

[anzial]

I'm sorry if this has been asked before, and I did try searching to no avail. So, w/o further adue: I've swapped out D4 for D5 vario (couldn't stand the whine any longer) and it seems, that my cpu now idles 2-3C higher than before. Everythings else is completely the same, same system, same loop, only different pump. I admit, the loop has not been completely bled (i'm on T-line), so is that the reason? or does D5 at its highest setting run hotter than D4?

[Rike]

I know that the D5 vario at it's highest setting does provides a little more flow and head than the D4, but I can't believe the heat dump difference could lead to a 2-3 C diff in your CPU temps. You could test this by running at the "4" setting on the D5 vario pot; I understand that setting is roughly equivalent to the normal output of a D4. Of course, there are variations in equipment and you'd have to be sure your ambient temps are around the same as your ambient temps that your normal reading are based on, but you could at least see if it make a difference from one setting to the next.

Personally, I'd guess that the additional flow would provide more cooling than the additional heat dump from the slightly faster pump, but that's a shot in the dark.

[SoulsCollective]

I'd say bubbles. I've noticed that temps just after filling a loop can be a good 5-7 deg C higher than you can expect after it's fully bled. Of course, this will depend on what block and rad you're using, but given that the D5 is a faster pump than the D4 and you're only using a T, turbulence and bubbles will be a bigger problem than they would with the D4.

[anzial]

I've got AC so it's safe to assume that ambient temp is the same. I'm hoping that a little air in the loop that hasn't bled yet is inhibiting the cooling rather that the new pump. On the other hand, I do have the pump just before the CPU block so if D5 does run hotter and dumps that much more heat, it goes right into the cpu rather than dissipating through the rad first :)

[Martinm210]

I'd give the bubbles a chance, although it's possible setting 5 does dump more heat, I can't seem to find specs on the old D4.

At 1.5GPM I found the D5 setting 5 to consume around 20 watts and that goes up to about a maximum of 24 watts with no restriction at all.
http://www.overclock.net/gallery/data/500/Pump-D5-9.jpg

At worst though, I would think you could lower heat dump and closely match the D4 with a lower setting. It wouldn't be the first time I've heard someone mention they've achieved better results with a lower setting...a little tinkering can go a long way.

Many people think more pumping power is always better. The truth is the best pumping power is the optimal amount which may not necessarily be setting 5 depending on your block and radiator setup.

Cheers to tinkering, I think you can find that sweet spot, just wait until the loop has settled in and play around with a few settings.

[anzial]

I think it was air, after all, a day later after the swap temps are pretty much the same (maybe D5 is about 1c hotter at setting 5). Thanks for the suggestion, Martin, I'll certainly tinker with it and see if lower settings do me any good :) I know that much that at setting 1 I lose about 3c at idle although I haven't tried load as yet :)