Check your mobo chipset type, wiki has a nice table of FDI complient mobo's (FDI stands for Friendly Display Interface) if you have FDI then you should be able to run 3 monitors, even on a HD 2500, but make sure your monitors that run on the digital outs (HDMI and DVI) have same pixel counts and refresh rates. If you have FDI then you can also run a PCIe dedicated card and still use your onboard graphics ports for more monitors (requires some careful setting up in BIOS), just follow the matched digital output rules again. With Nvidia that's 2 monitors on dedicated and 3 on your mobo, grand total 5 monitors, if you have an AMD dedicated graphics card you can run 3 and 3, grand total 6. The down side of all these setups is you can only run games on your primary monitor. Note: basic Windows Vista and 7 will only ever run 1 monitor. Goodluck 😀