OK...there are two things that will make a BIG difference.
First is the driver version. That is the biggest factor in 3D benchmarks.
Just as an example. I have an ATI X800Pro and with the driver with the unit I was getting 5292 and when I upgraded to the lastest driver I am now getting 9272 just by changing the driver.
The second biggest factor is 3D quality and resolution.
Turn "OFF" AA and Aniso in the graphic card settings.
Turn you resolution to 1024 x 768.
If both your friend and yourself do these things exactly, then your scores should be about the same.
Other differences can be in the RAM speed, quality of RAM, processes running the background, anti-virus software, whether STEAM is running or processing, etc.
Hope this helps.
Soyo Dragon Ultra Platinum Edition powered by a P4 3.06GHz w/HT @ 533FSB
ATI Radeon X800Pro 256DDR <---Yeah!!! I finally got it!!!
1024MB PC3200, Creative Audigy LS, 2 x 40GB = 80GB RAID 0
Windows XP Pro, DOOM 3, CS, UT2004, BF1942 RtoR, CNC Generals
Finished Half-Life 2!!!!!!!!!!