Computer Specs: Radeon™ HD 4870 Vs HIS Radeon HD 4670 w/ IceQ

This is my computer specs:

1. Asus P5Q-SE/R + E7300 (stock)
2. Team Elite 2GB Kit
3. Hitachi 250GB SATA II
4. Palit Radeon™ HD 4870 Sonic Dual Edition 512MB (Turbo Mode)

This is my boyfriend's computer specs using the same monitor settings (i.e. 1024x768x32bit).

1. DFI LanParty DK P45 T2RS Plus + E5200 (@3.2GHz, 1.36v)
2. OCZ Platinum 2GB Kit
3. Western Digital Green 500GB SATA II
4. HIS Radeon HD 4670 w/ IceQ (CrossFireX, 2 cards)

My boyfriend had to invest on TWO HIS Radeon HD 4670 w/ IceQ to match my ONE Palit Radeon™ HD 4870 graphics card!! I'm not sure if overclocking actually affect the results. But... WOOHOO!! My boyfriend is soooooo jealous right now. Cos he has no more money to buy the graphics card I'm using. HAHAHA! It cos my father $330 or something. $70 cheaper than previously sold. But my boyfriend said the price shot up again to $400!! Whoa! Siao.

I hope to buy a new monitor soon. Cos I'm now using an ancient one. Wakakaka! So I think a better monitor resolution might affect my computer's performance.