Tom's Hardware > Forum > Graphic & Displays > ATI > Radeon 4870X2 Question

Radeon 4870X2 Question

Forum Graphic & Displays : ATI - Radeon 4870X2 Question

Tom's Hardware: Over 1.4 million members in 6 different countries available to answer all your high-tech questions. Sign up now! Its free!

Ask the community Add a reply

Bottom Search this thread

I recently ordered a Sapphire 4870X2 after reading this review, plus a few others.

One thing that has me slightly confused however is at the bottom of page 2 where it states

Quote :

For all intents and purposes, the X2 behaves like a card equipped with 1 GB of available memory, just like the GeForce GTX 280.

I thought the card had 2GB of video memory, so I'm wondering why I've seen multiple reviews say the card only has 1GB of available memory. Have ATI just put "2GB" to make the 4870X2 sound better or is all 2GB going to be useable.

Message edited by ranky26 on 08-29-2008 at 07:40:15 AM

Add a reply

It has 2GB total, but "only" 1GB usable per card.

Reply to Avenger_K

Right, so then why would ATI even bother putting 2GB on the card in the first place?

Maybe I don't understand the reason for putting 2GB total and only 1GB usable on a card, but it sounds like ATI are just wasting 1GB for no reason.

Reply to ranky26

When they tell you there are 2gig, it's just a marketing ploy. They should be MADE ( by law ) to say that the cards only have 1gig because that's all that's available.

Reply to swifty_morgan

Yep, thats exaclty what I thought. Not to worry, everything I've read about the 4870X2 leads me to believe that its not suffering due to the "loss" of half its memory

Reply to ranky26

I may be mistaken, but I believe the problem (if you want to call it that) is that while both cards have 1 GB each (totaling 2 GB), the contents of the memory must be duplicated for each card to be able to render it's share. That is, the way the load is balanced in SLI and Crossfire (an expert could confirm this, perhaps) requires that each card have everything loaded into memory. So while there are 2GB of physical memory, you can only load a total of 1 GB of data (but you load it twice, spread out of 2 GB of physical memory). As I understand it, the only way to avoid this situation is to change the way the cards share the load.

So, to surmise the situation, the fact is that these cards do have the advertised amount of memory. However, when people say things like "you need X ram to play this game or to play this game at a certain resolution", you will need twice that amount of memory (total) in a dual-card setup.
If ATI said that this card had 1GB of memory, people would assume that it had 512MB of usable memory.

Reply to MattC

Swifty, 2 GB is available, you can access it for GPGPU and other apps, however currently the typical gaming mode is to have it mirror the information essentially giving you 1GB.

But yeah you work hard on that legislation.
Forget something important, gotta protect the gamers from their own stupidity. :lol:

------------------------------ You need a license to buy a gun, but they'll sell anyone a stamp (or internet account) - RED GREEN. GA to SK
HD Freedom: 45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
Reply to TheGreatGrapeApe

what I was getting at is that the advertising is misleading the public................... hence the beginning of this thread............ this guys not alone.

Message quoted 1 times

Reply to swifty_morgan

I've always been a strong believer in bit rate/clock speeds over raw memory ever since I got a 6600GT (128MB version that slammed the 256MB 6600).

Thanks for responses guys, I'm think I understand what is going on now. Am I right in thinking that one 4870X2 has 2GB, of which data is loaded into memory twice, similar to a raid-1 setup?

Message quoted 1 times

Reply to ranky26

ranky26 wrote :

Thanks for responses guys, I'm think I understand what is going on now. Am I right in thinking that one 4870X2 has 2GB, of which data is loaded into memory twice, similar to a raid-1 setup?

Yeah it's a similar idea, it that there's no increase in memory size nor in bandwidth, the difference of course being that it's not done for redundancy on a single processor, it's done for 2 separate processors.

swifty_morgan wrote :

what I was getting at is that the advertising is misleading the public...................

Because multi-gpu setups are so new and no one can research them?

Quote :

hence the beginning of this thread............ this guys not alone.

Just because alot of people think one way doesn't make that correct, acceptable, nor the responsibility of others.

There is 2GB on the card, I haven't seen much that says ATi or nV are trying to fool people with their X2 / GX2 cards, and of the two configurations, 2GB doesn't offer much above 1GB, whereas the 1GB on the GX2 and HD4850X2 would be limited compared to a full 1GB of available buffer space.

It has 2GB total, but "only" 1GB usable per core

Reply to Paris Lee

Wow a slam from the Ape albeit deserved. If you want to see deceptive marketing look no further than the iPhone 3G. ATI is not doing anything deceptive and I'm proud 4870x2 owner though my first one was defective.

Reply to bydesign

http://www.albinoblacksheep.com/flash/posting

woohoo, i get to post this again, so many times i get to post this. (my new fad)

------------------------------ I'm a git, deal with it.

Antec 1200,PC Power & Cooling 750,Gigabyte DS4-x48,Intel Q9550@3.4 W/Xigmatek S1283,8GB OCZ DDR2 800,ATI 4870X2,X-FI>CA 640C amp>Tannoy R300/Senn 595's
Reply to strangestranger

I think what sm may be confused about is when a low end card comes out with 1 gig of memory on it, thus it really is a decpetion, as those low end cards cant ever use that amount of ram, as they arent fast enough, nor "wide" enough

------------------------------ I went drifting, thru the capitols of tin, where men cant walk and cant freely talk, and sons turn their fathers in
Reply to jaydeejohn

he's been around long enough to know what is what.

Ask the community Add a reply

Tom's Hardware > Forum > Graphic & Displays > ATI > Radeon 4870X2 Question

Go to:

Help |
Forum rules

There are 1185 identified and unidentified users. To see the list of identified users, Click here.

Page generated in 0.482 seconds

Please mind

You are about to answer a thread that has been inactive for more than 6 months.
If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.

Add a reply Cancel

Focus On

Radeon 4870X2 Question

Forum Graphic & Displays : ATI - Radeon 4870X2 Question

Please mind