I reverse built a trading box. I started at the monitors and worked backwards. I ended up with the Asus P5K64WS mobo. It has four PCIeX16 slots and serveral more lesser x8, x1, etc. slots. It's marketed as a workstation mobo capable of 8 monitors, but with quad head gpu's it can run 16 monitors. And that's not even counting putting more GPU's in the lesser slots. Watch your power supply loading as you pile on more GPU's. There are plenty of power supply calculators available online where you can tell it how many of what you have in your system.
For anyone planning to run more than 2 monitors, "starting with the monitors and working back toward the mobo" is the only sensible way. "PSU Loading" isn't really an issue with workstation cards. While a "single display gamer card" can draw >300W all by itself, a quad workstation card draws only about 35 watts.
If you can build a computer I would recommend you custom builder your computer. Expecially if you will need a really powerful machine to run 8 screens. I built mine with a barebone kit from www.tigerdirect.com .
Just to come back to this thread and S's "That's SUPPOSED to work" caveat. Investigated the HP - it has 2xPCIEx16 Expansion slot 1 PCIe x8 (x4 electrical) 2 PCIe Gen2 x16 1 PCIe x1 (half-length) 3 PCI (full-height/length) 1 16-in-1 Media Card Reader (optional) Just looking at that spec rather than the detailed spec I would have assumed that it would run a minimum of 2x 4 port PCIEX16 for 8 monitors, maybe 1 more two port in another slot. BUT they tell you in the spec that it will run 1xNVS450 OR 2x NVS 290 OR NVS 440 with 1xNVS290 - in other words max 6 monitors via PCIEx16 slots. Fortunately the warnings given by S and others here made me check further. Whether or not it will run 2xNVS 400 old PCI in PCI slots I have yet to determine. The lesser model I mentioned above apparently has no BIOS restriction on running graphics cards in PCI slot but HP sales are dubious as to whether its 250w power supply will support 2 cards (maybe they are thinking 256MB PCIE or 3d cards). Checking the wattage with calculator as suggested I would draw 235W - If anyone can tell me if that is enough excess that would be appreciated. http://thermaltake.outervision.com/Power Thanks to all for suggestions and caveats that have helped me to avoid an expensive mistake. I will probably build backwards from the monitor setup as suggested. Alternatively I can try the two NVS400's I bought for $50 each in the cheaper box and if it doesn't work it has enough spec to serve as a data crunching box that has to be replaced anyway.
1. You always have to be suspicious of the "info" you get from Sales people... HP, Dell, or anybody. As multi-monitor is a Windows Extended Desktop feature, it's likely the info about "how many monitors" will run is false. Sales people are almost never up to snuff with info about multi-card, multi-monitor. 2. What computer are you looking at with only 250W PSU? Any decent computer today would come with at least 350W PSU. As I suggested before, the HP xw4600, has 475W PSU. 3. On the "wattage calculators", they always show maximum numbers.. such as would be drawn in the most powerful game or other such application. With workstation video cards in an trading environment, power usage will run around 180W or less.... so 350W is plenty.
Quantity of electrical connectors coming off the power supply is a consideration. Scat can probably tell you if you can put "Y" adapters in there to branch the 12v circuits and what happens to the wattage if it even is possible. Just a thought that came to mind; gotta make sure you can plug it all in.
Those wattage calculators try to account for all peripherals... 2 or more HDDs, 2 optic drives, Floppy, USB drives + miscellaneous... most things add only 5-10W or so (each) to the total... except for high power and especially dual high power video cards. Generally, any computer you buy will have an adequate PSU for just about any "normal" configuration you'd be able to run in that computer... except gaming video cards. As they can run 300W+ EACH, you'd often have to replace the PSU anytime you upgraded to a performance video card. A lot of people fret needlessly over the power of the PSU... but it's rarely a genuine consideration until you start dealing with the highest performing gamer video cards. Here's a recent article about contemporary graphic cards' power requirements. http://www.xbitlabs.com/articles/video/display/gpu-power-consumption-2010.html After reading this, you'll probably get the idea that recommendations of "850-1000W need" are mostly bunk... If you're running workstation video cards for trading, 350W is probably OK... most workstations come with 400-500W, or more, in base configuration.
The most recent NVIDIA driver supporting the NVS 400. http://www.nvidia.com/object/winxp_2k_94.24_2.html This driver doesn't work with the NVS 450 (or 290/295, for that matter).