Crossfire

#1

So lets assume I run crossfire on 2 HD 4890.

One has two DVI outpus, the other 1 DVi and a HDMI

I currently have two DVI and I have to constantly swap one to alternate between my TV (which is linked to the HDMI using a DVI/HDMI Adaptor.

Does this mean I could effective run the TV from one card and the dual monitors from the other card…so no more swapping???

Oh I also assume I am going to have to upgrade my power supply. If so can you point out one at UMART that you think will be good, keeping in mind im a tight ass. :slight_smile:

#2

I’d have to read up on this to be sure, but if you are running two monitors off one card, and the TV off the second, the cards will not be running in crossfire but as two individual cards.

What that means is that you will not gain any gaming performance from adding the second card. Two monitors and CF will work fine, but not 3 monitors with a 4000 series card.

If you buy a 5000 series card, then you can use eyefinity which allows you to run up to 3 monitors off one card, or 6 off two cards.

For a PSU, can you tell us what you are currently using as it may already be adequate.

#3

just looked up the the 4890 in crossfire draws about 420 watts … anothing above … what … a 750 would be more than fine

#4

Not quite, that would be total power draw for the entire system, not just the 4890s. The difference between full GPU load and idle GPU load is roughly what the GPUs draw. It’s no where near 420W, it would be closer to ~200W. Add on the power consumption of the rest of the system (CPU, motherboard, fans, hdds, etc) and then you would be closer to the ~400W mark which is possibly a minimum figure.

So in reality, a PSU with roughly 500W - 600W would do the job as long as your system isn’t a total power hog. To give further examples, my system which is over clocked and running similar GPU power only draws 550W from the socket under 100% CPU and GPU load (Furmark and Prime95 running at the same time). Under normal conditions, it is much lower again.

Still, I like to play it very safe, so I have a 1.05kW PSU. Main reason being is that I should never be in a situation that will make me question whether I have enough power.

What’s also more important to determine is the amperage that is provided on the 12V rails. That is why I would like to know what model PSU you have.

#5

ive got a themaltake 750 but decided against buy the 2nd card. I big up to 110 but it went for a little more…fuk its second hand…they can have it.

Ill sit on what ive got for a while and will look at a card that runs three monitors shortly

thanks for the investigation guys

#6

No worries.

In any case, your current power supply should be adequate for whatever you decide to upgrade to, 750W gives you a fair bit of headroom.