Thursday, January 29th 2009
RV740 to Make Radeon HD 4730, HD 4750 SKUs?
AMD is on course of releasing the industry's first GPU built on the 40nm silicon process: the RV740. Its specifications make it a cheap yet powerful GPU for the segment it is about to cater to. With the earliest pointers hinting at 640 stream processors and a 128-bit wide GDDR5 memory interface. The GPU also marks the industry's first mainstream implementation of the GDDR5 standard.
Fresh details emerging out of the inspection of the driver information files of ATI Catalyst version 9.1, as German website ATI Forum finds out, hints at the possibility of the RV740 being implemented in two SKUs: the Radeon HD 4730 and Radeon HD 4750. While in the driver file, the device string lists with "RV630", it can be seen throughout the file that several strings are assigned to the same RV630, and is merely a means to identifying a whole class or generation of graphics processors to the driver. Additionally, the string bears the device ID of the RV670, again, that's not relevant. The strings are what matter. The RV740 is not very far away from large scale production. It should become a reality by the upcoming CeBIT event, in March. From the view of being a mere postulation, RV740 being the GPU that goes into making the new SKUs, does end up sounding plausible. When released, these cards are intended to further strengthen AMD's market position in the sub-US $150 market.
Source:
ATi Forum
Fresh details emerging out of the inspection of the driver information files of ATI Catalyst version 9.1, as German website ATI Forum finds out, hints at the possibility of the RV740 being implemented in two SKUs: the Radeon HD 4730 and Radeon HD 4750. While in the driver file, the device string lists with "RV630", it can be seen throughout the file that several strings are assigned to the same RV630, and is merely a means to identifying a whole class or generation of graphics processors to the driver. Additionally, the string bears the device ID of the RV670, again, that's not relevant. The strings are what matter. The RV740 is not very far away from large scale production. It should become a reality by the upcoming CeBIT event, in March. From the view of being a mere postulation, RV740 being the GPU that goes into making the new SKUs, does end up sounding plausible. When released, these cards are intended to further strengthen AMD's market position in the sub-US $150 market.
15 Comments on RV740 to Make Radeon HD 4730, HD 4750 SKUs?
Just so you know -- GDDR5 with 128-bit should be comparable to GDDR3 with 256-bit (please correct me if I'm wrong). I'm just amazed that GDDR5 is cheap enough where it's more profitable to pair it up with a 128-bit interface that it is to just go with regular GDDR3+256-bit.
4750:
640 shaders
32 tmus (22.4 gt/s)
16 ROP (11.2 gp/s)
128-bit
700/3600 (900 Gflops, 57.6gbps)
50-60W
4730?:
640 shaders
32 tmus (18.4 gt/s)
16 ROP (9.2 gp/s)
128-bit
575/2000 (736Gflops, 32 gbps)
compared to:
4850:
800 shaders
40 tmus (25 gt/s)
16 ROP (10 gp/s)
256-bit
625/2000 (1000 gflops, 64gbps)
110W
4830:
640 shaders
32 tmus (18.4 gt/s)
16 ROPs (9.2 gp/s)
256-bit
575/1800 (736 Gflops, 57.6gbps)
110W
To find your answer, compare the numbers in the parenthesizes.
Memory: the same as 4870, rated at 4ghz...meaning with half the bus, it has the same bandwidth of 4850. Of course both could be subject to overclocking, achieving ~70gbps. A draw, give or take. (~2200mhz, 4400mhz.)
Core: We know the 4850/4830 are cores that didn't make the 750mhz cut at the required voltage, and thus used in parts with lower voltage, again limiting their potential to around 700mhz. The 4750 will not be constrained by this binning...At worst held back to not impede on the 4800 series. If it a comparable size/tdp to rv730, and I suspect perhaps a little less, I think it's logical to agree they will behave similar. RV730XT's, not unlike rv770XT's, can hit 800+ mhz. It might even do a little better.
So taking these constraints, or lack there-of, we could see something like this:
4850: 680/1100 (~1.1 TF, 70gbps)
4750: 850/4400 (~1.1TF, 70gbps)
What's interesting is that RV740 is a perfect 80% part vs Rv770...so they should stack up fairly evenly at proportional clockspeeds, except for that fact they both have 16 RBE's (ROPs). Therefore, in cases where pixel-pushing is needed, even at stock vs 4850, overclocked, or anywhere in-between, it could be the faster card at anywhere up to 12-25%.
I think that RV740 will go a long way to showing Rv770 was ROP-limited in many cases, and that this combination (640sp/16 ROP...or 320sp/8 ROP) at ATi's faithful clockspeeds is a more optimal arrangement. This can be shown by overclocking a 4830 vs a stock 4850.
:toast: