ATI 48xx sreies crossfire

[Stan300]

I'm thinking of crossfire and i have some questions. I have ATI saphire 4870 and i want to upgrade to crossfire. Would it be better to get another 4870 or should i get 4870 X2. Which would run better. I read somewhere that because the 4870 has 512MB GDDR5 so the X2 uses also 512 mb GDDR5 giving the total of 1GB. Is that true. And also how much power would i need for 2 4870's and 4870 + 4870X2. I have a pentium q6600 processor and ASUS P5E motheroard. Anyway this is my first post - my first question and i hope you will be able to help me. Thank you.

[DMB2000uk]

Welcome to the forums Stan.

What power supply do you currently have?

What resolution do you game at?

Yes, there are two lots of 512MB on the 4870X2, but although it totals 1GB of video memory, you can only make effective use of 512MB of it, as due to the way crossfire works effectively the same data will be stored in both cards while they each render every other frame (this works the same when it comes to two separate crossfire cards).

Dan

[Stan300]

Thanks DMB2000uk for sucha fast reply. Currently i have a 550watt power suply and i play my games at 20" resolution. Do you think this would be enough power for two 4870's.

[DMB2000uk]

Can you be a bit more specific please, who makes your PSU (and what model is it). The PSU brand matters quite a lot as PSUs can vary so much in quality between a decent 550W and a cheap 550W PSU.

I take it you are gaming at 1680x1050? At that resolution just two 4870's would be more than enough.

Are there games where you currently find your graphics card lacking? (i.e. you cant play smoothly at the quality settings you want).

Dan

[Stan300]

So my components are:
ASUS P5E motherboard
Intel quad core q6600 2.4GHz
2x2GB DDR2 RAM 800MHz
one ATI Saphirre 4870 graphic card
640GB HDD 7200rpm
ATX 550W green power super silent power supply (40-50EUR)
P.S. i also have a TV card and a sound card. If i want to add another ATI Saphire 4870 would 550W be enough power or should i get more.

[DMB2000uk]

You should get more, but make sure that it is a quality brand PSU and not the cheapest available.

Check out here for who to trust:
http://forums.legitreviews.com/about7169.html

Dan

[Stan300]

Alright. So waht about if i need the maximum 850W and decide to add smt in the future. Would my components be in danger if i buy a 1000W PSU, if i only need 850W.

[DMB2000uk]

You can buy a massive 1000W PSU if you really want to (and it wont damage anything in your computer), but you will be wasting your money.

All you really will need is a decent 600-700W PSU.

I'd recommend a Corsair 620HX. They are capable of powering everything but the most extreme setups.

Here is a graph of some high powered setups (from LRs testing):


Take the 4870X2 (not the Crossfire X result as that is two of the 4870X2s), as being about where your crossfire power draw would be, even throwing in a few more components and you will still be sitting happy with the Corsair PSU.

Dan

[Gomeler]

I second the HX620, it's a rock solid PSU and sufficient for dual-GPU setups. 4870x2 CrossFire just gets obscene

[Apoptosis]

I second the HX620, it's a rock solid PSU and sufficient for dual-GPU setups. 4870x2 CrossFire just gets obscene

I have four of the Corsair HX620W power supplies and all have been used for nearly two years now and they are still rock solid. The only thing they have ever failed me on was a pair of Radeon HD 4870 X2 graphics cards in CrossFire and even then they ran the game, but the performance was low and the images were messed up at times in only certain applications.

[Stan300]

OK. So three more questions: if i buy the antec twelve hundred case which has 6 fans does every fan has its own connector and where do i connect them ( are there enough connectors on the Intel DX48BT2 or do i coonnect the fans directly to the PSU). And does it matter which way do i put in the DDR2 RAM and is it any different to connect DDR3 RAM. What about if i want to instal a bigger fan for the processor - do i need to aplly another layer of thermal paste, or do i lean the previous one than aplly it or is it okay to leave it. Thanks.

[DMB2000uk]

The fans on the Antec 1200 come with pass through molex connectors, so will plug into your PSU.

DDR2 RAM has a notch on it, and it will only line up and fit into the slot one way round. DDR3 RAM is very similar, but has the notch in a different place, so will not fit in DDR2 motherboards, and conversely DDR2 will not fit in DDR3 motherboards. To make sure your memory is running in dual channel mode put the matching pair of sticks in the same coloured slots (so both in blue, or both in black).

The DX48BT2 motherboard has instructions on how to insert your DDR3 RAM into the board on page 38.
(Which can be viewed online here)

If you are installing a new heatsink on the CPU, then you will need to clean off the old thermal paste on the CPU and apply some new thermal paste. Then you can mount the new CPU heatsink.

[Stan300]

Thanks DMB2000uk for clearing that out (sorry for those noob questions). So back to the topic. What is the main difference between crossfire and crossfireX. How would a system with a 4870 and 4870X2 perform (or would it be better to have just two 4870's). I heard that if theese two cards are in crossfire it only uses 1GB GDDR5 RAM so wouldn't it be better to have just one 4870X2? Would there be an options to turn off one of the cards during program work or smth. and turn it back on when playing games. How would this perform on the ASUS rampage formula?

[DMB2000uk]

At your native resolution (i.e the physical pixels in your monitor) of 1680x1050 (Is that correct?), having 1GB of video memory will give you very little performance improvements over the same 512MB card.

As you already have a 4870, it makes sense just to get a second and run them in crossfire. If you were buying them separately, I would have recommended a 4870x2 as they are cheaper, but it makes more sense to just get another 4870 in this case.

I think crossfireX is just crossfire renamed since it was able to support more than two cards.

What will you be doing that requires crossfire to be disabled? It's perfectly do able in the software to enable and disable it when you do and don't want to use it.

Dan

[Stan300]

So how much of an improvment would i have with another 4870? And also how much better would one 4870 and one 4870X2 be over the two 4870, and for the price is it even worthet?

[smack323]

Unless you are not getting the performance out of your games currently..ie: choppy gameplay - you might not notice any improvemnt by adding a second card.

[Stan300]

OK. So what about the motherboards. I know that the intel chipset supports ATI videeo cards and nVidia cards (not SLI). How about the nVidia chipset - does it support one ATI graphic card?

[martini161]

supports it but wont do crossfire

[Stan300]

So if i were to buy a nVidia chipset motherboard like the Asus P5N-T Deluxe could i put on ATI 4870. I know it wont do crossfire but will it run just one ATI card. And aslo what is better 8GB DDR2 800MHz RAM or 4GB DDR3 1333MHz RAM. Thanks.

[DMB2000uk]

8GB is overkill, and there is very little difference in performance from the faster memory. So unless you are planning on overclocking your CPU lots, then a 4GB 800Mhz kit will do you just fine.

The Nvidia boards will support just one ATI card fine (or two running separate monitors, but not crossfired together)

Dan