ATi Radeon 4890 Discussion

[mhouck]

april 6th

VR Zone Article

 

[bryanW1995]

Originally posted by: thilan29

Originally posted by: TC91
I don't have a thermometer but room temps should be about 20-25c; right now its freezing cold up here in Canada (Edmonton) so my room temps are probably a bit lower. I am using the cosmos 1000 case, it has four 120mm case fans, but i recently removed the two at the top and there is no difference in gpu temps, but cpu temps are lower and the system is quieter.

Well it doesn't seem you have bad airflow...I dunno, maybe since your card was an early version the silicon ran a bit hotter than the newer silicon? No idea.

Lol I'm in Edmonton too...and it's not fair that it's like -15C in March!!! I went out today and it was pretty damned cold with the wind.

yeah, I feel your pain. I'm in san antonio, it got down below 50 today!!

 

[thilanliyan]

Originally posted by: bryanW1995
yeah, I feel your pain. I'm in san antonio, it got down below 50 today!!

:|

 

[SlowSpyder]

Originally posted by: mhouck
april 6th

VR Zone Article

Wow, looks like things are going well for their new cards. I just wish we could get some real concrete info on the 4890.

 

[nace186]

the inquirer say it's simply a much higher clocked 4870 with a new board.

 

[SSChevy2001]

Personally I can see ATi activating the extra 100 SP on the card, besides a bump in clocks.

 

[Keysplayr]

Originally posted by: SSChevy2001
Personally I can see ATi activating the extra 100 SP on the card, besides a bump in clocks.

Why didn't they in the first place? It might have given them an edge. Yields?

 

[Cookie Monster]

Nope. The extra ALUs breaks the balance of the set ratios of the RV770 architecture. Like clusters have set number of ALUs/TMUs for e.g, you cant add x into the exisiting specs without re-configuring the cluster specs.

As for yields, Id say the redundancy techniques are paying off quite well.

 

[error8]

Originally posted by: keysplayr2003

Originally posted by: SSChevy2001
Personally I can see ATi activating the extra 100 SP on the card, besides a bump in clocks.

Why didn't they in the first place? It might have given them an edge. Yields?

Yeah, I don't think there is any possibility to activate anything on this chip. If it was, Ati would have done it and they had a single gpu competitor by now for GTX 280-285.

The highly overclocked and "volt modded" 4870 sounds more plausible to me. Add some GDDR5 at 4.4-4.6 ghz and the card can easily obtain up to 20% in performance over the current 4870, at least in some situations.

 

[dflynchimp]

memory bandwidth doesn't account for that much performance impact at this point. 4.4-4.6GHz on GDDR5 looks pretty, but 20% improvement is delusional. Even if you were to clock the GPU 20% up (to 900MHz core up from 750) the scaling still wouldn't be 100%

 

[error8]

Originally posted by: dflynchimp
memory bandwidth doesn't account for that much performance impact at this point.

It might count with the gpu at 850-900mhz. It's not memory bandwidth starved now, at 750 mhz, but higher, it might be a different story.

Originally posted by: dflynchimp

4.4-4.6GHz on GDDR5 looks pretty, but 20% improvement is delusional. Even if you were to clock the GPU 20% up (to 900MHz core up from 750) the scaling still wouldn't be 100%

That is true, but this is why I've said 20% more performance in some situations. Anyway this 20% is just the rumored extra performance of the 4890. Maybe ATi is aiming for lower then that.

 

[evolucion8]

Originally posted by: dflynchimp
memory bandwidth doesn't account for that much performance impact at this point. 4.4-4.6GHz on GDDR5 looks pretty, but 20% improvement is delusional. Even if you were to clock the GPU 20% up (to 900MHz core up from 750) the scaling still wouldn't be 100%

I think memory bandwidth does a difference in the HD 4x00 series architecture, the HD 4830 performs so close to the HD 4850 considering that the former one is missing 160 stream processors, but the difference between the HD 4850 and the HD 4870 is much bigger than that.

 

[AzN]

Originally posted by: evolucion8

Originally posted by: dflynchimp
memory bandwidth doesn't account for that much performance impact at this point. 4.4-4.6GHz on GDDR5 looks pretty, but 20% improvement is delusional. Even if you were to clock the GPU 20% up (to 900MHz core up from 750) the scaling still wouldn't be 100%

I think memory bandwidth does a difference in the HD 4x00 series architecture, the HD 4830 performs so close to the HD 4850 considering that the former one is missing 160 stream processors, but the difference between the HD 4850 and the HD 4870 is much bigger than that.

4850 is not far off 4870. 4870 is 20% faster than 4850 but than again the core is clocked much higher. 625 vs 750.

As for 4830 and 4850. It's about 15% difference. Then again clock difference is merely 50mhz. Performance discrepancy comes from shader and tmu units but I've heard RV770 is really 32TMU card and later added 8TMU. Something about those 8TMU not really doing anything.

RV770 with only 16ROP and 40TMU it's pretty much efficient with 256bit bus. Of course the extra bandwidth does play some role in ROP and AA performance with 4870.

Overclock a 4850 to 4870 core clocks and you would easily find all the bandwidth is really doing. I suspect not much.

 

[SSChevy2001]

Originally posted by: Azn
Overclock a 4850 to 4870 core clocks and you would easily find all the bandwidth is really doing. I suspect not much.

This review should answer that question. There are cases where the extra bandwidth helps a lot, and other cases where's it's not needed.

http://www.xbitlabs.com/articl...024mb-gs_11.html#sect1

 

[bryanW1995]

Originally posted by: keysplayr2003

Originally posted by: SSChevy2001
Personally I can see ATi activating the extra 100 SP on the card, besides a bump in clocks.

Why didn't they in the first place? It might have given them an edge. Yields?

Normally, I would just think that they're bumping the clocks and that's it. However, they played this sneaky cat and mouse game last time to great effect, so I wouldn't be surprised to see the extra 160 sp's enabled AND a speed bump, too. I'll be happy with my gtx 260 either way, however, as I don't see nvidia being able to drop prices much more on that unit and the gtx 275 doesn't look to be much of an improvement.

 

[AzN]

Originally posted by: SSChevy2001

Originally posted by: Azn
Overclock a 4850 to 4870 core clocks and you would easily find all the bandwidth is really doing. I suspect not much.

This review should answer that question. There are cases where the extra bandwidth helps a lot, and other cases where's it's not needed.

http://www.xbitlabs.com/articl...024mb-gs_11.html#sect1

Nice link.

AA performance is definitely up there with bandwidth. Minimum frame rates help too.

 

[BFG10K]

I've removed the off-topic messages referencing Chizow and Wreckage.

Seriously guys, let's stop this nonsense and stick to the topic at hand.

Video Mod BFG10K.

 

[Cookie Monster]

The RV790 is the real deal as seen here.

-edited-

 

[dug777]

Originally posted by: Azn

Originally posted by: SSChevy2001

Originally posted by: Azn
Overclock a 4850 to 4870 core clocks and you would easily find all the bandwidth is really doing. I suspect not much.

This review should answer that question. There are cases where the extra bandwidth helps a lot, and other cases where's it's not needed.

http://www.xbitlabs.com/articl...024mb-gs_11.html#sect1

Nice link.

AA performance is definitely up there with bandwidth. Minimum frame rates help too.

Here's my GRID comparo with core past 4870 speeds, mem essentially at stock.

http://forums.anandtech.com/me...id=31&threadid=2281917

COD4, Lost Planet and FarCry:

http://forums.anandtech.com/me...242119&highlight_key=y

 

[bunnyfubbles]

Originally posted by: Cookie Monster
According to this, GDDR5 clocked at 5Gbps for RV790
The HD4870 uses GDDR5 rated at 3.6Gbps.

Where does it say anything about GDDR5? I think you're somehow confusing the PCI-e 2.0 5GT/s lane transfer rate spec for somehow relating to the boards memory bandwidth.

According to vr-zone, the memory is only going to be bumped up to 975MHz from 900MHz...

 

[ghost recon88]

GPU Cafe is reporting it's a whole new ASIC and not just a super clocked RV770.

Atleast according to the latest round of emails sent out today. The branding could however change as there is still quite some time for the launch, which as we told you earlier is slated for the 8th of next month.

The details of the ASIC are listed as 800 stream procesors combined with upto 200MHz core clock increase over the Radeon HD 4870. Interestingly the memory specification was moderately bumped by 50MHz only. AMD has been very successful with all the smoke and mirrors during the RV770 launch, we wouldnt be surprised if it was the case again.

UPDATE:

A few more details; new board design and a completely new cooling solution. We can confirm that it is new ASIC and not a speed binned product.

 

[mhouck]

Sapphire 4890 listed Tech Connect

 

[ghost recon88]

Originally posted by: mhouck
Sapphire 4890 listed Tech Connect

Someone over @ XS said it best regarding that.

That means jack.. a portuguese store has had a "HD4890" in their website for 3 weeks now.

That could very well be just a fabrication from the store, based on rumours around the web.
Many stores do that to get more hits and pre-orders.

 

[Cookie Monster]

Originally posted by: bunnyfubbles

Originally posted by: Cookie Monster
According to this, GDDR5 clocked at 5Gbps for RV790
The HD4870 uses GDDR5 rated at 3.6Gbps.

Where does it say anything about GDDR5? I think you're somehow confusing the PCI-e 2.0 5GT/s lane transfer rate spec for somehow relating to the boards memory bandwidth.

According to vr-zone, the memory is only going to be bumped up to 975MHz from 900MHz...

Oh your right. Hmm late night posting can get to us sometimes

To redeem myself, here are some pics of the HD4890

 

[bunnyfubbles]

Originally posted by: ghost recon88
GPU Cafe is reporting it's a whole new ASIC and not just a super clocked RV770.

Atleast according to the latest round of emails sent out today. The branding could however change as there is still quite some time for the launch, which as we told you earlier is slated for the 8th of next month.

The details of the ASIC are listed as 800 stream procesors combined with upto 200MHz core clock increase over the Radeon HD 4870. Interestingly the memory specification was moderately bumped by 50MHz only. AMD has been very successful with all the smoke and mirrors during the RV770 launch, we wouldnt be surprised if it was the case again.

UPDATE:

A few more details; new board design and a completely new cooling solution. We can confirm that it is new ASIC and not a speed binned product.

hmm, I have been seeing 75MHz increase to the memory as opposed to 50. However I'd definitely take that highly negligible hit to the memory if it meant a 950MHz core as opposed to 850MHz...