No problems at all. If you have regular PCI slots then you can use either 1 4-port card or 2 2-port cards. One thing to keep in mind is ATI cards are not as compatible as others. nVidia cards often will work with Matrox but not always. So if you can, try to stay with same manufacturer or same type of cards in whole system. Like I said for MS Vista, video cards are trickier. But with XP, less so. As for which ones to buy... New... http://www.newegg.com/Product/Product.aspx?Item=N82E16814130289 http://www.newegg.com/Product/Product.aspx?Item=N82E16814130466 Used... http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=matrox+g450&_sacat=See-All-Categories You can get a couple of used Matrox g450 2-port fanless cards for $10-15 each. The only thing about them is they won't allow you to tilt your monitor in "profile" mode, other they're the cheapest way for pci slots and good for trading. Another option would be a used Matrox g200 pci for $30-40 I initially was buying cards with fans but have grown tired of the noise so wouldn't recommend them for trading. The nVidia NVS series are good but a more pricey option.
Matrox hands down. Specifically designed for financial and data feilds. I bought two quads on Ebay for half price. Turned out it was Goldman Sachs selling their excessees. Found out when the return name on the Fedex was Goldman Sachs.
After having two ATI-based video cards go bad (each after 1.5-2 yrs*), I followed the recommendations in prior threads to get an nvidia card (no fan). It's been about a year but everything is working well so far (knocks on wood). * - ironically in both cases, the company that actually manufactured the card went out of business around the time my cards failed. So, although both were under warranty, neither one was covered. R