HD3870X2: Debunked and detailed (56k massacre)

[Valtiel]

I've read around a few of the threads here, and it seems that there is some general confusion and misinformation. I'm posting this thread to try and clear that up a bit.

First I will start off with power consumption. The 3870X2 consumes roughly 200W of power at peak load

I took this quote from Hardware Canucks (review written by SKYMTL)

This test will be done a bit different from the last power consumption tests we have conducted. In this case Company of Heroes is now used with AA enabled to put less strain on the CPU so it will not impact as much on the results.

Please remember that this is the power consumption for the WHOLE SYSTEM.

Heat output (again taken from Hardware Canucks):

Source: http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/4236-ati-radeon-hd3870-x2-1gb-review-14.html

Second I want to clarify that This is indeed a PCIe 1.1a card and NOT PCIe 2.0. The two GPUs communicate over a bridge chip which uses only ~5w of power.

Length:

On the board we've got two 3870 GPUs, separated by a 48-lane PCIe 1.1 bridge (no 2.0 support here guys). Each GPU has 16 lanes going to it, and then the final 16 lanes head directly to the PCIe connector and out to the motherboard's chipset.

From Anand at Anandtech

Detailed specs:

Note the GDDR3 use vs. GDDR4 on HD3870. AMD has allowed board partners to use GDDR4 on the PCB so we may see GDDR4 cards in the future.

Link: http://www.anandtech.com/video/showdoc.aspx?i=3209

The GPU's themselves have a frame buffer of 512Mb each. Whether this equates to 1Gb of total usable memory or not, I have yet to find out. Since in SLI and Crossfire you generally do NOT add the memory up I suspect that the 3870X2 actually has 512Mb of VRAM, instead of 1Gb.

Overclocking:
The cards themselves have two onboard BIOS's (but it still suffers from the 862 Mhz Core-lock), this means that if you were to flash your card to a new BIOS you would need to do it twice. I'm fairly certain AMD will release a new BIOS to fix the 862-locked Bug, which doesnt allow core overclocking past 862 Mhz. It has also been speculated that AMD tightened the timings on the GDDR3 (for performance gains) conversely this means less overclocking potential. SKYMTL once again found:

Max Overclocks:

Core: 865Mhz
Memory: 1892Mhz (DDR)

These clocks represent a pretty pathetic overclock of 50Mhz on the cores and 92Mhz on the memory. Considering the GDDR3 memory is rated at 2Ghz (DDR) I would think that either ATI tightened the timings or there is insufficient voltage running to it to facilitate higher overclocks. The core is another matter altogether; all signs point to the dreaded issue that plagued the early HD3870 512MB cards which couldn%u2019t clock past the 862 to 867Mhz mark. These cards needed a BIOS flash in order to overclock past that point but flashing the BIOS on this card with two GPUs is a bit beyond the scope of this review. It is possible that this is an issue with our engineering sample and won%u2019t carry into the actual production cards.

 

[swifty_morgan]

I'm sorry if you feel I'm high jacking your thread, but after clicking on the first graph something comes to mind. How can they say it's a 1gig card. Just like all dual cards and sli set ups before it, 512 + 512 does not + 1gig. It's still "2" 512 cards is it not ???????............ splain

And I was looking today. You can get a 8800gtx for the same "449" price range.

But back to your thread........ I read several bits about the new card. A couple included the temperature data. These seem to be high compared to what I was reading elsewhere. Don't know the links offhand though.

 

[Valtiel]

The GPU's themselves have a frame buffer of 512Mb each. Whether this equates to 1Gb of total usable memory or not, I have yet to find out. Since in SLI and Crossfire you generally do NOT add the memory up I suspect that the 3870X2 actually has 512Mb of VRAM, instead of 1Gb.

But back to your thread........ I read several bits about the new card. A couple included the temperature data. These seem to be high compared to what I was reading elsewhere. Don't know the links offhand though.

Please note that SKYMTL was reviewing an engineering sample, therefore certain details are subject to change, such as heat production. This should be used as an example.

 

[Shadow703793]

^Agreed. ES have a tendency to be bad or good depending on the sample.

 

[Wisecracker]

I've read around a few of the threads here, and it seems that there is some general confusion and misinformation. I'm posting this thread to try and clear that up a bit. .....

Second I want to clarify that This is indeed a PCIe 1.1a card and NOT PCIe 2.0. The two GPUs communicate over a bridge chip which uses only ~5w of power.

.....

On the board we've got two 3870 GPUs, separated by a 48-lane PCIe 1.1 bridge (no 2.0 support here guys). Each GPU has 16 lanes going to it, and then the final 16 lanes head directly to the PCIe connector and out to the motherboard's chipset.

From Anand at Anandtech

The HD3870x2 interface is PCIe2 x16. The bridge chip which connects the 2 GPUs is PCIe1.1 .....

I imagine the day will come when the bridge may evolve to PCIe2 (or 3) but at 4 GB/s I don't think PCIe 1.1 x16 is quite bandwidth strarved ...

 

[kpo6969]

http://www.guru3d.com/article/Videocards/490/
http://www.tomshardware.com/2008/01/28/ati_r680_the_rage_fury_maxx_2/index.html
http://enthusiast.hardocp.com/article.html?art=MTQ1NCwxLCxoZW50aHVzaWFzdA==
http://www.anandtech.com/video/showdoc.aspx?i=3209
http://www.tweaktown.com/reviews/1281/1/page_1_introduction/index.html
http://techreport.com/articles.x/13967
http://www.techpowerup.com/reviews/HIS/HD_3870_X2/
http://www.hothardware.com/Articles/R680_Has_Landed_ATI_Radeon_HD_3870_X2/
http://translate.google.com/translate?hl=en&sl=de&u=http://www.computerbase.de/artikel/hardware/grafikkarten/2008/test_crossfire_sli_einzelkarte/&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://www.computerbase.de/artikel/hardware/grafikkarten/2008/test_crossfire_sli_einzelkarte/%26hl%3Den%26sa%3DG
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/4236-ati-radeon-hd3870-x2-1gb-review.html

Why not just put all the info out and let the individual decide? I have no opinion either way.

 

[righteous]

I look at it this way.

It's a fast card that is the most current with dx10.1 capability.
I could care less what it is, or how many cores and what the power consumption is. It performs at a point where it competes in the high end for a price that destroys the competition.

What more can one ask for?

 

[Wolfshadw]

Funds to purchase new system components at will?

-Wolf dreams

 

[kpo6969]

My take on it (and the 9800GX2) would be not to make a rash purchase of either, maybe a wait and see approach would be better. Both cards may have their issues:
3870 x2: drivers
9800GX2: heat and power requirements

 

[soundefx]

The thing is, driver updates are an easier to fix than heat and power problems.
I am not a fan of either company, but it seems as if Ati is making a big come back. I guess they learned a little after the year of being wooped on by nvidia.

 

[random1283]

Well if the 9800GX2 is %30 faster than the ultra than it will be %20 faster than the 3870X2 with drivers I think the 3870X2 could make it
%5 - %10 but that just depends on the 9800GX2's real performance or if it's another phenom scenario

 

[spoonboy]

I'm sorry if you feel I'm high jacking your thread, but after clicking on the first graph something comes to mind. How can they say it's a 1gig card. Just like all dual cards and sli set ups before it, 512 + 512 does not + 1gig. It's still "2" 512 cards is it not ???????............ splain

And I was looking today. You can get a 8800gtx for the same "449" price range.

But back to your thread........ I read several bits about the new card. A couple included the temperature data. These seem to be high compared to what I was reading elsewhere. Don't know the links offhand though.

Put it this way, how else would you describe it?

If someone said "how much memory does this card have?" what would you reply?

 

[TheGreatGrapeApe]

You could answer, each VPU has access to 512MB, so while the card has 1GB it really just acts like a very large 512MB card (for most things, you can actually use the memory cumulatively but you need apps that can do that, and most games are not coded to do so).