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Entries on Tuesday 28th February 2006

entry Feb 28 2006, 02:15 AM
I read a lot of C/O Forum entries before I did this. Here's one that was especially informative:
http://www.cubeowner.com/forums/index.php?...9372&hl=28+volt

The main idea was to take power robbing hardware away from the VRM/PSU to provide more onboard power for the Video Card. In my case, this was accomplished by:
1. PLX CPU with VRM Bypass. For a dual processor like my 1.7GHz this can be as much as 30w at full load. Power is direct from one of the 28v Apple PSU pairs, no VRM involved.
2. ADC to DVI Adapter used to power Apple ADC Cinema Display. The 23" HD Cinema is rated at 70w. The Cube PSU is taken out of the Monitor power loop.
3. GigaDesigns VRM to give increased power reserve to remaining hardware. See this article for more info on this VRM: http://www.novaint.com/gigadesigns/newscvrm.html
4. Remove Optical Drive, to prevent spinup power surge, about 10-12w. This may not have been necessary, I am just playing it safe. The extra room in the Cube makes cooling the VRM easier too.
5. Using External Self Powered FW Optical Drive. The FW Ports can supply up to 10w each, using a self powered device this is reduced.

Entries on Tuesday 21st February 2006

entry Feb 21 2006, 07:25 PM
Just a follow-on note about heat and the Black Sapphire 9800.

The VRAM and the GPU chip (dye) produce a lot of heat, but that is easy to address. The other components also produce quantities of heat and need help in an enclosed space.

On the top of the card, near the VGA connector are several components that have a heat dissipation plate on the underside of the card. When installed in a Cube, this plate sits directly over the VRM socket on the Mobo. The VRM Relocation extension cable plugs into the Mobo VRM socket and the wires are routed down to the relocated VRM/Bracket between the HDD and Optical Drive (mine is removed). Unfortunately this dissipation plate leaves little tolerance between it and the VRM extension cable wires, it actually rests on the wires. I placed some high heat tolerant tape there as a chafing guard, not much I can do about the parts touching there. But, I decided that if the components on the top of the video card were cooler, things may not be so bad.

This is where the Zalman helps again, it moves so much air and the cooling fins actually direct air all over the top of the 9800. So, with this in mind, the Cube must be in the upright position for proper heat ejection. I noticed that if I ran a test while the Cube was laying on it's side the heat would keep building. I flipped it upright and the heat stabilizes at 66-67C. With the Cube on its side the CPU is also directly under the GPU, and heat is radiated upward to the bottom of the 9800, not good.

The external, self powered FW/USB 2.0 ADS enclosure and NEC 3550a DVD-RW help reduce heat by leaving space around the VRM/HDD for cooling and reducing watt load demand on the Giga VRM.

Dave

Entries on Monday 20th February 2006

 | Category: Video Cards
entry Feb 20 2006, 07:14 PM
I have a Black Sapphire 9800 running in my Cube right now (I purchased it from 'sgtwicki' from C/O Classifieds).

My Cube was configured with: PLX dual 1.7GHz with VRM bypass, Spirica VRM Relocation Kit, 250GB Samsung Spinpoint HDD, Pioneer DVR-K05 DVD/CD. After reading all the info I could about this type project I decided to try it. Special thanks to Dave P., hpence, TomD, Gene Hack, Mig and all the Pioneers in this type effort. If I forgot anyone, thank you too.

January 28, 2006
To start, I pulled the optical drive and used the 12v Molex for the Black Sapphire 9800's power. I pulled the modem for space and ventilation. I just plugged it into a normal Cube PSU, I'm using a newer one I got with a DVIator. I put heat sinks on the VRAM and a better fan on the card for heat. I taped pins 3 & 11 so it would work in an AGP Mac.

Jan 29, 2006
As everyone might imagine I had a couple of freezes. It wasn't heat because the case is off and I'm showing 47C from the Temp. probe under the upgraded fan, just warm to the touch on the VRAM heatsinks. I was worried about the Apple VRM not doing the job, too weak. I purchased a a Giga Heavy Duty VRM, no more freezes. I've got the card installed properly in the chassis now, snug you might say. Still using power from optical drive molex and standard Cube brick.

It will not fit in the original case, the card 12v power wire extends past the top metal chassis (near the Cube on/off button). In addition, the card fan won't clear, just a bit too high. This will only fit in my PLX Case, if I get that far.

Performance? Seems awful fast although I don't have the optical drive in it yet.

February 3, 2006
Four days after installing the Giga VRM and it's still working.
No hiccups/freezes/KP's. In the PLX case the ventilation is good and that helps it run at decent temps. I'm sure the VRAM heatsinks and better fan help too. It's sleeping/waking and in general running as well as the other 9800's I have (in Mac big boxes).I still haven't got the DVD/CD installed, waiting for parts. I'll test games when I do.

February 17, 2006
The Cube/9800 is still running nominal. This is looking like it might work, no surprises. I still thought the card was susceptible to heat during Gaming or H.264 movies, so I searched for a solution.

Finding a really good fan/cooling system that would circulate the air in the stuffy Video compartment and fit a 9800 was easier that I thought. I had a Zalman V700CU (all copper) fan on another 9800 so I tried it. It fit the Black Sapphire and with careful installation I was able to shoehorn it into the PLX Clear Case. The Zalman looks cool thru the Clear Case, blows the air around superbly and at 28d, is fairly quiet.

The Zalman really works. I ran a H.264 movie for an hour and the 9800 stabilized at 66-67C, CPU at 69-70C.

I then ran the Halo Time Demo from my FW DVD/CD. Settings are all High and FSAA 4X. The 9800 is set at stock freq's - 351/324. See results below:

Date / Time: 2/18/06 6:58:45 (0ms)
1700MHz, 1536MB
CubeK\Games\Halo\Halo Frames=4700
Total Time=194.20s
Average frame rate=24.20fps

I used XBench but the test was a little depressing, only 43. I don't think XBench really measures things properly.

A couple pictures of the Zalman running on the 9800, in the PLX Clear Cube are in the C/O Gallery.

So far, so good. I'm still testing things but my Cube runs and feels like a 'real' computer now.

Dave


 
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