[Wizdumb]

I've been thinking about adding an additional graphics card to my PC. I am running a HIS Radeon 4850 HD 512mb DDR3, Ive read when using crossfire you dont need to exact same card but the same series (4800). I just wanted to see if I would get the best performance with the exact same card, or if I were to get an HIS 4850(or 4870 DDR5) 1GB and if I should allocate the larger card to physics or rendering? Don't get me wrong I can pretty much max out any game with the OverDrive but I want better FPS at 1920x1080 and use tripple buffering. I have my opinions, I dont know if they're right or wrong so if someone could please help me out?

Wizdumb.

[Muffin Man]

well, if your gonna xfire, you should do it with another 4850, dosen't matter what brand

if you pair your 4850 with a 4870, then i think the 4850 will be holding the 4870 back from using all its performance.

on the other hand, if you get a 4830, it might hold your 4850 back. i would just get another 4850. as far as allocating one card for physics and rendering, ill let someone else respond to that.

also, you have to make sure your psu has enough juice to power xfire'd cards.

[synergy]

Not entirely sure, but I think GPU physics processing is exclusive to Nvidia at this time.

[Wizdumb]

Would the memory size matter?

[hikaricloud]

Only matters at higher resolutions, really.

[Wizdumb]

I know, I mean if I run a 512mb and a 1gb crossfire would the performance be better than 2x 512's? @ 1920x1080

[Druid]

Originally Posted by synergy

Not entirely sure, but I think GPU physics processing is exclusive to Nvidia at this time.

I think so too, but I think gpu phsysics processing is pretty dumb. It should be done on the cpu. The gpu is already doing so much work compared to the cpu. If it was done on the cpu, your performance would be better unless your cpu really sucked.

Originally Posted by Wizdumb

I know, I mean if I run a 512mb and a 1gb crossfire would the performance be better than 2x 512's? @ 1920x1080

I'm not sure. I'll let someone else answer.

[Wizdumb]

Thankfully I have a core 2 quad Q9550. My performance is great if I use the CCC Overdrive, but I want better....But oh yeah my PSU will support X-fire no problem, it even came with 2 seperate pci-e power cords.

[baron5]

You can crossfire with the 1gb but it will only use 512mb of that memory (1GB total, 512 each card), you see with crossfire both cards need to share the same attributes otherwise it would be difficult to spread the work across evenly.

just get another 512mb HIS 4850, To be safe tell us what psu you have or send us a link and we will check it out.
Newegg.com - HIS H485FN512P Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Desktop Graphics / Video Cards
or from here
SuperBiiz.com - HIS ATI Radeon HD4850 512MB DDR3 2DVI/HDCP PCI-Express Video Card

[Wizdumb]

Thanks for the confirmation, I thought it would be better to get another 512. Here is my PSU.
Newegg.com - CORSAIR CMPSU-650TX 650W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7 Power Supply - Power Supplies