So I finally decided to try a different pump...
The revised CSP-750 Mark II pumps, like those sold by D-Tek Customs, have two slits cut into the motor housings to prevent overheating of the motor. Unfortunately, this also became a major noise leak. This was never a problem with the CSP-750 Mark I pumps (like the ones that failed on HammerSandwich and his friend) or the initial CSP-750 Mark II pumps without cutouts, such as those sold by Bigfoot early on. I was using Bigfoot, uncut pumps when Dave from C-Systems decided to send me revised pumps, telling me that it would be best to do a review based on the revised model. Not until I received the revised pumps did I realize the mistake they made in cutting out those slits!
In the end, I had to deny them a review because it would simply end up very negative, due to out-of-box acoustic performance. Although, as you see in my previous images, I was able to do some crazy looking mods on the pumps to block out most of the noise they emitted, they did, nevertheless, still make more noise than the previous CSP-750s, and at this point I deemed them inadequate for silent PC building. Around this same time, HammerSandwich's Mark I (which I sold him, in perfectly fine working order, I might add...
) and his friend's failed them. Hammer was wise enough to do some price shopping and came across a holiday special from Danger Den whereby there's a nice discount on all orders over $200; so, I chipped in and we made an order for three pieces, bringing the total above $200 and netting us a decent discount (sufficient for offsetting the additional cost of having two of the pumps redistributed).
Obviously, integrating the Laing DDC (aka Swiftech MCP-350) into my system would take major changes. I had to switch from two pumps with 1/2" fittings to a single pump with 3/8" fittings. On the same token, I felt that if I'm going to go through the trouble of (yet again... *sigh*) draining and dismantling my system's liquid cooling loop(s), I might as well take the opportunity to make other changes to the system. My focus was two-fold: decrease temps and
decrease noise. So, what did it take to do this? Well, I had to do a little more than a pump swap, of course...
First thing to deal with, is that, as some might recall, I had an imbalance in air flow. My front radiator was flowing much less air than my rear radiator, even though the fan, radiator and shroud were identical, and both were blowing out through grille-free openings. I realized that it wasn't so much as the front exhaust being excessively restrictive as it was that my rear exhaust was flowing very, very freely; I decided to take advantage of this, by upgrading the rear radiator. I swapped out the rear Black Ice Pro for a Black Ice Xtreme.
I had experimented with using a second fan, blowing through the front exhaust, to help bolster flow through it. What I discovered was that in the case of my system, having a second fan blowing through helped flow of the front exhaust quite a bit (two fans in serial). The reason for this remains unknown to me, but the fact of the matter is that a fan, spinning around ~900rpm, to support the Nexus 120 that's pulling, improved flow by some ~75%, judging by the highly (inaccurate
) anemometer I have with me--my hand. So, long story short; after I had assembled the new loop, I did lots of air flow and temperature testing and achieved a very good balance, whereby I added aluminum Evercools to the blowing in side of both radiators (the front one, in particular, fully shrouded) and have them software regulated to remain relatively slow, and spin only fast enough to improve air flow dramatically without adding much perceptible noise.
My next objective was to deal with the new pump. As I said, the switch is from dual cooling loops with dual 1/2" fitted pumps into a single loop with a 3/8" fitted pump. Moreover, I can no longer rely on the direct-to-block pump setup because the new pump's inlet and outlet are parallel. In the end, I took a queue from HammerSandwich and suspended the pump off of the reservoir (having only one loop now, I was able to dump the second reservoir, too), pumping back up a bit into the front radiator, then from the front radiator into the GPU block, then into the CPU block, then into the rear radiator and finally back to the reservoir. The best part of all? I was able to retain the major ease of use factor--I can still do as much as a whole mainboard swap without even draining my cooling system!
Next, I took the opportunity to remove the mainboard, making room to take out the PSU and mod it. I removed the two stock fans from the OCZ PowerStream 420, which, while relatively smooth, spun much too fast. In place of the rear (exhaust) fan, I installed a Nexus 80mm fan and ran its wire out the front of the PSU, where the rest if its cables come out. The front (intake) fan was removed, then the motor and blade assembly were cut off the frame, and the frame was reused to mount the wire grille to the PSU (not very restrictive, but important for safety; I don't like the idea of possibly letting stray wires or other things get into a gaping maw in the front of the PSU. Plus, this looks more well finished. Doing this mod alone dropped system noise a significant amount.
Finally, I did an analysis of the voltage I was feeding to my CPU in order to achieve the overclock that I had, and found it peculiar that I was using so much more voltage than others (everyone was using no more than maybe 1.75V while I was at 1.9!). I did some playing around with it and realized that by backing down on my memory timings a tad, I could shave over .15V off the Vcore and still have 100.00000% stability. It must've been something about the memory controller on the CPU wanting a whole lot more voltage for a negligible gain in memory performance (in my case-the only difference lie in very obscure timings controls that aren't even available on other mainboards).
On with the pics!!!
An overall view of the machine with the side panel removed.[/url]
The rear radiator has grown considerably in depth, and this image provides a good angle to compare it against the front radiator, which is identical to what used to be in the back. As you can see, the new loop still allows me to just bend everything out of the way to make room for relatively effortless components swaps. The AF92CT doesn't ever turn on; it's just there to help support the weight of the video card, which sags under the weight of the Danger Den NV-68 block if not supported. The pump is suspended, and gently set on top of some foam, primarily to keep it from leaning into the side panel and making a massive humming racket. The RAM looks funny because I removed the heatspreaders from them, but they're two 512MB sticks of PQI Turbo PC3200.
Here's a closer look at the pump and the front exhaust.[/url]
I would consider suspending the hard drive were it not for the fact that doing so would take away greatly from the system's ability to travel without having to open it up and make preparations. This is, still, meant as a portable, liquid cooled overclocked gaming rig. Now, it happens to be very quiet to boot.
Here's the upper section behind the front.[/url]
The change to single reservoir is visible here, as are the lines into and out of the pump, into and out of the front radiator, into and out of the CPU block and into and out of the GPU block. As HammerSandwich suggested, I was able to completely eliminate 180-degree bends. I apologize for the poor cabling; there was just too much of it to deal with.
The pump and GPU block from a different angle.[/url]
Supplemental rear exhaust fan that only activates at higher temperatures,[/url]
CPU block from another angle and the lines into and out of the rear radiator.
I had a bit of difficulty trying to get that rear fan to stay due to the way the rear radiator is mounted, but I finally figured it out and used foam to wedge the fan in from both sides (can't see it, the way it's done). The computer doesn't normally sit so close to the wall during operation, but when shut off, I push it back towards the wall so it's not as easy to trip on, like during my quick photoshoot this evening (it's all on the floor; I got these angles by using a minitripod right on the floor). The depth of the machine had gotten too much to deal with on top of my shallow desk, so I placed it, for safety reasons, on the ground.
That sums up yet another entry in the log. Any bets as to what I (might) do next?
Btw, temps are down across the board thanks to the combination of less voltage, more flow and more radiation. Noise has been cut by a huge margin, and I can easily sleep in the room with this computer on, under load.
In fact, I did all my stability & stress testing overnight for several nights with this machine and it didn't affect my sleep one bit.
Per usual, I'm looking for comments.
EDIT: Minor fixes for spelling, vocabulary and grammar. Took out some extraneous content.