I just got my new computer built yesterday and when I was looking around in the ATI Catalyst program I noticed that under graphics hardware the memory says its 512MB. Has anyone else had this problem? I want to make sure I dont have a bad card because it should say 1GB.

Crossfire and SLI do not add memory; all texture data etc. is mirrored to both GPUs memory so there is only 512MB of RAM actually available.

But it's not using crossfire or SLI. It's 2 gpus on one card.

Heyyou27 is right  
Read this:
 
http://www.tomshardware.co.uk/foru [...] sfire-faqs
 
AMD/ATI HD 3870X2(Warning:The HD 3870X2 is NOT 2 cards (like Nvidia 9800GX2).Its actually 2 GPUs on one card and it has 1 PCB* compared to 2 PCBs of 9800GX2)
 
Also:
http://www.xbitlabs.com/articles/v [...] -x2_3.html
 
Memory Size : 2x512MB

But it is using Crossfire to connect the two GPU's its just doing it on one card. Instead of using a bridge connector like you would with two cards the X2 has a chip between the two GPU's making the connection.

Ok, you are linking to yourself as a "source" for your post..... that proves nothing.

It makes absolutely no difference if the electrical connections between two GPUs are on one PCB, or if there are connectors linking 2 PCBs. I really don't see how you could be confused enough to think there would be.

How do you think the GPUs split the graphics load? Its in the exact same manner that a pair of GPUs in crossfire would, by either Supertiling, Scissor Frame Rendering, or Alternate Frame Rendering.

You still have two copies of everything in RAM, there is still 512MB per GPU, there are still some games that wont work well or at all with 2 GPUs that will only run with 1 GPU (games ATI have no Crossfire profile in their drivers for).

The 3870X2 is Crossifre-on-a-card. How many PCBs it has is irrelevant and doesn't change that, or make it faster or slower than a dual PCB design.

You are seeing 512MB as you have two GPUs on a card, each with 512MB. It should not say 1GB.

Yes it is using Crossfire. It uses the exact same methods to get its two GPUs working together as a pair of cards in Crossfire. Thanks to the PCIe "hub" on board, each GPU even thinks it is connected to a separate PCIe slot. They just share power circuitry and a PCB/cooler.

Nothing is wrong, that's just the way it is. In the wonderful world of Crossfire and SLI, 512MBx2=512MB.  

Of course the 3870X2 uses Crossfire. Funny that you would buy one and not be aware of this fact...
 
In any case 512MB should be enough for the vast majority of games, so don't sweat it.

Yeah, basically there is 1GB of memory physically on the board but it's split between the two GPUs and each GPU has to have the same data in it's memory.

Try Everest, SiSoft Sandra or GPU-Z.

I have 2 x 3870's in xfire and CCC only sees 512mb in graphics hardware as well, but two cards appear in the overdrive section('select gpu to configure') and I have a xfire section below this with an enable/disable option(the beauty of two seperate cards due to xfire problems in games!). We have all the 'advantages' of 1gb gpu memory but our systems only see 512mb, vista as well, which is a good thing because vista doesn't subtract 1gb off available memory then due to it's memory mappings, only 512mb. According to windows task manager, I have 3070mb available memory with 4gb physically installed on vista32bit. Vista uses about 1.2gb of that for itself so I have nearly 2gb for games(slightly off topic!). It's a win win situation big buddy!