Low and behold another major GPU leak has just surfaced on the SiSoft Sandra benchmarking database. Yesterday we caught a glimpse of the possible specifications for Nvidia’s GM200 GPU. Today we take another possible glimpse at what AMD has been cooking. There is no way to confirm this leak or the prior GM200 one. so I’m going to go ahead and label this as a rumor for the time being.

Let’s get straight to it. According to the database listing the GPU will feature 64 GCN CUs/Compute Units. For a total of a whopping 4096 GCN cores. The GPU will also feature 4GB of 3D stacked High Bandwidth Memory / HBM modules clocked at 1.25Ghz.

AMD Radeon R9 390X / Fiji XT Is an Impressive Beast

According to the official specifications of HBM.  A one Gigabyte HBM stack clocked at 1.2Ghz provides 128GB/s of bandwidth. Due to the intriguing facets of how this memory architecture behaves, the increments of bandwidth are additive with each subsequent HBM module.  With four HBM stacks for a total of 4GB you’re looking at 512GB/s of total bandwidth.

This leak indicates that the HBM modules on the R9 390X have been clocked slightly above the default 1.2Ghz frequency to 1.25Ghz. Which should drive overall bandwidth up to ~533.3GB/s. That’s more than double the memory bandwidth available to the GTX 980 which is 224GB/s. And easily surpasses the 320GB/s bandwidth of the R9 290 series and the 336GB/s data rate of the GTX 780 Ti. The R9 390X has by far the greatest amount of memory bandwidth we’ve seen on any graphics card to date.

 
The database for Fiji includes two entries. The earlier one at October 20 strikes me as slightly unusual. The GPU is clocked 200mhz below the latter entry at October 28. And the memory is clocked significantly lower at 350Mhz down from 1250Mhz.  While it’s certainly unusual it’s not unexplainable. The earlier entry could possibly be of a very early engineering sample. Where only functionality was being tested rather than the stability of the chip or the clock rates.

At 4096 stream processors and 533GB/S we’re looking at a 50% increase in SPs over Hawaii (R9 290X) and a more impressive 66% improvement in memory bandwidth. So this card should be an absolute monster at high resolution gaming such as 4K or Eyefinity. The previously leaked liquid cooling shroud for the card has turned out be only one of four prototypes according to Videocardz. So we might actually see the R9 390X release with both liquid and air cooled reference designs.

 Interestingly enough the leaked specifications for GM200 also has it outnumbering the CUDA cores of GM204 (GTX 980) by 50%.  So it seems great minds think alike, as both red and green have opted for a similar generational leap. With the exception of AMD going with HBM approximately a year earlier than Nvidia. As green intends to use that technology with the Pascal graphics architecture in 2016.

Below you’ll find the specifications for both GM200 and Fiji X exactly as they were found in the SiSoft Sandra databse. I’ve added both current flagships from AMD and Nvidia for reference. This should only serve as a guideline based on the recent SiSoft Sandra leaks.

Like I said earlier none of these database leaks can be verified. However they do give us an idea of what to expect. And the specifications listed here are certainly not out of the realm of possibility. In fact they’re very much where one would expect them to be. More should come to light as we approach 2015.

Read more: http://wccftech.com/amd-fiji-r9-390x-specs-leak/#ixzz3Im2Yp200

Cool.

The rumor mills always have a field day with this kind of clickbait ahead of major GPU releases.

I've followed this stuff since the 80s, and this list of rumors is clearly created by someone who tried hard to make it look realistic, and failed. It's like a spec-sheet for a 14nm or 16nm GPU (true full 14nm lithography, not 20nm/22nm finfet).

Why? Because what we're talking about here would end up being significantly larger and hotter than GTX480 was on 40nm, along with correspondingly higher power consumption.

It's not entirely unlikely that HBM might be ready in small quantities, but I also think that's more likely to hit around Q3-Q4 2015.

As a rumor is looks good (so a beast of a GPU), but why would AMD go with 4GB of VRAM when some current games are already asking for more?

^ This.

We really need more than 4gb of vram my 780ti tri sli is crying... its godly power is held back by its miniscule vram at 4k.

Well not really, only in a few games I've had to turn down textures a bit, but 6gb vram will soon become the norm for 4k gaming.

Actually, RAM is not much of a bottleneck with the actual cards. Some board partners have launched 8GB versions of the 290X and at least the Sapphire one doesn't perform so much better than a 4GB regular one.

http://www.tomshardware.com/reviews/sapphire-vapor-x-r9-290x-8gb,3977.html

(note that both are clocked at the same speeds)

But I was thinking more about the games asking for more than 4GB of VRAM to use the highest settings.

This will probably be a decent Crossfire choice if the price is right. Still think I'm gonna go ahead and get the GTX 980 though; the power consumption and noise are also a huge factor for me (don't want to replace the PSU before I rebuild the whole thing).

I have 3dfx Voodoo II 12MB is that good.

I also have 3dfx Voodoo Banshee(EWW!!) & Voodoo 3 3000 16MB. So good...

Can't wait to see this HBM works.