It will fit
http://www.swiftnets.com/products/mcw50.asp
Quoted for Swiftech Site
"The MCW50™ ships with a dual retention mechanism composed of spring loaded screws providing off-the-shelf compatibility with all ATI® Radeon™ products (including the latest X800 series) as well as nVidia® GForce™ families of products up to the GeForce 4.
Optional hold-down plates are available for nVidia FX, PCX, GeForce 6 and newest G70 series with their respective retention kits as shown below. The product can also be installed with other graphics processors by using permanent bonding agents, such as thermally conductive epoxies. Swiftech guarantees compatibility with ATI and nVidia reference models only. "
If you happen to upgrade to the ati x1800 tho you will be out of luck as they use the 4 hole mounting, the two hole mounting solution applies to all 7000-8000-9000 and x000's and x1300-x1600 but im not sure about the x1650
heres the list of 4 hole mounting GFX cards from nvidia the ones that say yes you would need to purchess a hold down plate for it to fit.
http://www.swiftnets.com/products/NV...PATIBILITY.asp
im not sure how all the no's are mounted so im not gonna say yes or no with these do you own research.
try looking alittle harder next time, this was found using google on the first page in less than 5 min