ATI Radeon HD 3870 CrossFire Video Card Review

[maj0r_pawnage]

planning on buying new intel quad core in january and upgrading to x38, i wonderin if i could maybe even grab a few 3870x2's

[maj0r_pawnage]

hmm i dont think my 550 watt psu can handle them though, im wondering is it possible to grab another 500w psu i got and use that to power my gpu's alone with the one i have powering the rest of my system?

[DL126]

hmm i dont think my 550 watt psu can handle them though, im wondering is it possible to grab another 500w psu i got and use that to power my gpu's alone with the one i have powering the rest of my system?

Take a look here.
I'm running a 250 watt version of it. (Appears as though they have discontinued my model)

http://www.thermaltake.com/product/Powe ... /w0157.asp

[martini161]

yea, but you would have to set up some kinda relay so that both psu's come on at the same time

[DL126]

yea, but you would have to set up some kinda relay so that both psu's come on at the same time

It's done for you martini161.
You just plug it in and go!

I've installed 3 of them.
It doesn't get any simpler.
The only thing I've found that someone might not like is that a slot in the back of the case is occupied by the additional power cord needed by the xtra power supply.
I suppose one could actually get around that by drilling a hole somewhere and running the cable thru that instead.

[maj0r_pawnage]

seems that no one sells the 450w version

[martini161]

yea, but you would have to set up some kinda relay so that both psu's come on at the same time

It's done for you martini161.
You just plug it in and go!

I've installed 3 of them.
It doesn't get any simpler.
The only thing I've found that someone might not like is that a slot in the back of the case is occupied by the additional power cord needed by the xtra power supply.
I suppose one could actually get around that by drilling a hole somewhere and running the cable thru that instead.

yea, but when you press the power button on the computer, it sends a message to the motherboard, that sends a message through the 24pin power connecter to the psu that tells it to come on. if a powersupply is not hooked up to the mother board then you have to have a relay that tells the second psu to come on, or else what ever is hooked up to it wont get power

[DL126]

yea, but when you press the power button on the computer, it sends a message to the motherboard, that sends a message through the 24pin power connecter to the psu that tells it to come on. if a powersupply is not hooked up to the mother board then you have to have a relay that tells the second psu to come on, or else what ever is hooked up to it wont get power

No disrespect intended here ...
But am I not explaining this correctly?
Or are you just wanting to make a mole hill into a mountain?

It's simple ...
It uses a "Y" harness to tap into your existing 24 pin MOBO harness.
When you press the power button ... they both come on at the same time.

There is nothing else to be set up by the installer.
You just plug the thing in and hit the button.

Look here maj0r .....
http://biz.tigerdirect.com/applications ... CatId=1076

[Apoptosis]

Back to the Radeon 3870.... Start a new thread for PSU stuff.

[Mercyreaper]

Hey everyone just joined the site, I have visited a few times and I am always happy with the information. With the new 3850 512MB cards will there be a revisit to the crossfire benchmarking for an update, and of course the quad 3870s?

Another question as well, do you think multi GPU scaling will be that much different with the 3870's? I mean will 4 3870's beat out 2 3870 X2?

[Apoptosis]

Hey everyone just joined the site, I have visited a few times and I am always happy with the information. With the new 3850 512MB cards will there be a revisit to the crossfire benchmarking for an update, and of course the quad 3870s?

Another question as well, do you think multi GPU scaling will be that much different with the 3870's? I mean will 4 3870's beat out 2 3870 X2?

I'm not sure which one will be better four 3870's or two R680's, but I do know the two things that will matter most... The drivers and of course the available bandwidth in the pair of x16 PCI Express 2.0 slots... R680's are rumored to be clocking better than the R670's and if their clocks are a bit higher could there be a limitation in the PCI Express lanes? Too early to tell, but I know R680 will be out first and CrossFireX drivers are looking like Feburary at the earliest.

[Ramzii]

Hmm good question 2 x 3870(X2) or 4 x 3870 (single GPU) cards...

Well the way I see it PCIe 16x v2.0 has theoritically double the bandwidth of the v 1.0/1.1 countpart on the old Motherboards.
and if your using and 790FX motherboard that is fully 2.0 compliant rather that an some 2.0 over a 1.0 bridge like on some boards, you should get the equivalent bandwidth of PCIe 32x in v1.0 ... As for the cards 3870 cards using all the bandwidth not likely perhaps the R700 highend multi GPU boards next gen might come close.

Current GPUs seem to require 8x PCIe per GPU minimum to operate ... which means 4 GPUs maximum on the current chipsets with 32 to 36 PCIe pipes i.e. 2 x (16x) + 1 x (4x) or 1-4 (1x)
the motherboard do have 4 PCIe 16x slots, which when more than 2 GPU are using go 8x mode for 4 gpu or 16x + 8x + 8x for 3 Gpus.
Note: 8x on a v2.0 PCIe is equivalent of 16x on a v1.0 PCIe as far as bandwidth is concerned.

What will come into it for speed is:
[*] what speed GDDR3/4 memory is used (the faster mhz or least latency)
[*] what CAPacitors they use from one brand to the next
[*] what type of headpipe and coolers they use

if you plan to go water cooling only the first two will matter as a customer re-fit willl most likely be required.
Otherwise for air cooled GPUs those will matter and make sure memory on GPU is cooled both sides and good air around the GPUs
perhaps big side fan and/or flow fan run air over and under the motherboard.

The other thing that could affect it is how the GPU share or dont share the memory on single GPU card vs multi GPU.
if the multi GPU still go down the PCIe16x to swap between the GPUs RAM blocks I cannot see any major benifit apart from space.

Then the single units may cooler if effecitively and thus lend them self to better overclockability in the CATALYST drivers.

Overclockablility will depend on all these things to some degree as well as your rooms ambiant temperature.

[davyluu]

how come some of the games have crossfirex comparisons with the 8800 ultra and some don't? Doesn't seem very consistant.

[DMB2000uk]

how come some of the games have crossfirex comparisons with the 8800 ultra and some don't? Doesn't seem very consistant.

The ones where the crossfire results are missing are the games where crossfire doesn't work, so you have to use one card. This shows you the performance you can expect across all the games LR benchmarks rather than just showing the good ones where it works.

Dan

[junpei]

Any new news on wether or not we can run a pair of 3870x2's on a standard intel motherboard, i know intel are touting there new P45 and a pair of them as a "perfect match" but i dont want DDR3 just yet, but i do want a q6600 and a pair of those babies

[DMB2000uk]

As far as I know, if your board supports xfire with the 2 PCIE slots, you are set to go.

Woops, didn't see the x2 bit. I have no idea then

Dan

[Apoptosis]

Any new news on wether or not we can run a pair of 3870x2's on a standard intel motherboard, i know intel are touting there new P45 and a pair of them as a "perfect match" but i dont want DDR3 just yet, but i do want a q6600 and a pair of those babies

AMD has made a comment on the Radeon 3870 X2 series and CrossFire on the Intel board... To be honest they don't even have their drivers done yet, so not sure they can say for certain. Out of experience though, I'm fairly certain they will be supported on Intel CrossFire certified motherboards.

[jtclayton]

Hmm good question 2 x 3870(X2) or 4 x 3870 (single GPU) cards...

Most reviews show that the x2 has aprox 10-15% more power than dual 3870's...
x2's are going for aprox 450, and the 3870s are going for 250 (500 for a pair)...

Now take into account that at the time of this post (that i am aware of) there is NO MB out there that supports 4 x16 slots, they drop back to (x8's) when all 4 slots are populated on both the MSI and ASUS. *side note unless the pictures are distorted for the asus board it is NOT able to support 4 doublewide video cards it would only be able to support 3...

Back to the K9A2 Platnium & 3870s
So once the CrossfireX drivers are avail for twin x2's you should have aprox 220-230% power... over 4 3870s....
this is just a guessamation, atm but consider this is compairing 4gpu's that have x16 bandwith (plus the 10-15% boost) over 4 gpu's that will be choaked on x8 bandwith slots

As a reminder if your going this far with graphic cards you might as well consider going 790FX chipset so you have a motherboard that was designed to go with your video cards as there are many dual slot mother boards.

Reports on the x2's have also suggested that under max load the card will pull max of >>> 360 watts <<< (I do not know if this is true or not but it has been from one of the many reviews of the (MSI HD3870x2 OC) card

I myself am going with the MSI (when they get back instock) Video cards and the K9A2 Platinum MB...
J