ATI Radeon HD 4850 Review --- TheThirdMedia Hardware

Scaling New Heights

It's blockbuster season again and we don't mean that just for the movies. It's exciting times too in the graphics scene. Following NVIDIA's debut of its humongous next generation GPU that probably set a few records for size and power consumption, ATI has finally released its new Radeon HD 4800 series, consisting of the Radeon HD 4870 and the 4850. We managed to get our hands on the 4850 and will be looking at this performance mainstream GPU in this review.

We had to update our version of GPU-Z for the information about the Radeon HD 4850 to be shown correctly.

Long before they appeared in our labs, we have been hearing lots of good things about these GPUs based on the new RV770 core and its supposed launch date (and even managed to get some early performance numbers here.) In fact, we were half expecting to find these hot new graphics cards on show at Computex early this month, but alas, it was not to be. Which meant that NVIDIA once again got ahead of ATI in launching its GeForce GTX 280 and we already had our say about that here.

Of course, being the first to launch is not everything, especially for a US$649 part that's likely to interest only a niche group of consumers. ATI's new Radeon HD 4800 series and the 4850 in particular, however is a solidl mainstream part that's priced at a sweet US$199. Unlike NVIDIA which pushed its flagship GTX 280 out of the blocks first, followed by the GTX 260, ATI is only hard launching the Radeon HD 4850 this month. In fact, retailers are selling the 4850 cards even as we write. The higher clocked 4870 will only be available for sale officially in July, presumably due to the tight supply of GDDR5 memory used on that GPU. Meanwhile, the true enthusiast class GPU from ATI - known only by its R700 codename - is rumored to hit stores in early August. ATI does have the hardware ready for the R700, but they are putting on the final touches for it as well as conducting finalization and stability trials to ensure all goes well for the consumers.

In the table below, we have the specifications of these new Radeon HD 4800 cards along with some of their probable competitors in terms of price and performance:

Comparing the Radeon HD 4800 series

Model	RadeonHD 4870 512MB	RadeonHD 4850 512MB	NVIDAGeForce GTX 260 896MB	NVIDIAGeForce 9800 GX2 1GB	NVIDIAGeForce 9800 GTX 512MB	ATIRadeon HD 3870 X2 1GB
CoreCode	RV770	RV770	GT200	G92 x 2	G92	R680(RV670 x 2)
TransistorCount	956million	956million	1400million	1508million	754million	1332million
ManufacturingProcess	55nm	55nm	65nm	65nm	65nm	55nm
CoreClock	750MHz	625MHz	576MHz	600MHz	675MHz	825MHz
StreamProcessors	160 Processors (800Stream processing units)	160 Processors (800Stream processing units)	192Stream Processors	256 Stream Processors	128 StreamProcessors	128 Processors (640 Stream processing units)
StreamProcessor Clock	750MHz	625MHz	1242MHz	1500MHz	1688MHz	825MHz
TextureMapping Units (TMU) or Texture Filtering (TF)units	40	40	64	128	64	32
RasterOperator units (ROP)	16	16	28	48	24	32
MemoryClock	3600MHzGDDR5	2000MHzGDDR3	1998MHzGDDR3	2000MHzGDDR3	2200MHz GDDR3	1800MHz GDDR3
DDRMemory Bus Width	256-bit	256-bit	448-bit	256-bit	256-bit	256-bit
MemoryBandwidth	115.2GB/s	64GB/s	111.9GB/s	128GB/s	70.4GB/s	115.2GB/s
PCIExpress Interface	PCIe ver 2.0 x16	PCIe ver 2.0 x16	PCIe ver 2.0 x16	PCIe ver 2.0 x16	PCIe ver 2.0 x16	PCIe ver 2.0 x16
MolexPower Connectors	2 x 6-pin	6-pin	2 x 6-pin	6-pin, 8-pin	2 x 6-pin	6-pin, 8-pin
MultiGPU Technology	Yes(CrossFireX)	Yes(CrossFireX)	Yes (SLI)	Yes (SLI)	Yes (SLI)	Yes (CrossFireX)
DVIOutput Support	2 xDual-Link	2 xDual-Link	2 x Dual-Link	2 x Dual-Link	2 x Dual-Link	2 x Dual-Link
HDCPOutput Support	Yes	Yes	Yes	Yes	Yes	Yes
StreetPrice	US$299	US$199	US$399	~US$449- 529	US$199	~US$319- 365

A New Strategy

One could interpret this change in the order of how ATI launches its new GPUs as a signal that something has changed. You would be right and ATI has much to say about its new strategy for GPUs. In short, the company will build on what it did rather well with the Radeon HD 3800 series, which is to focus on the performance mainstream and produce a GPU that gives a compelling price to performance ratio. ATI plans to start from this upper mainstream GPU and then either scale up the price/performance table (by using a multi-GPU solution like the Radeon HD 3870 X2) or scale down as usual by having cut-down versions of the GPU architecture.

Of course, ATI backed up this strategic shift with the usual analyst findings (Jon Peddie Research) about the size and importance of this mid-range segment. Given that we personally wait for the performance mainstream variants to be available before considering any new generation GPUs, we believe this sentiment applies to many gamers also.

Coupled strongly with this focus on the mainstream is ATI's belief (or marketing slant) that the days of the all-powerful flagship GPU that is then gradually reduced to produce the mainstream and budget versions (like what NVIDIA has done with the GTX 200) are almost over. The reason being that these giant GPUs are using too much power to be efficient, even with all the new power-saving technologies and that the new benchmark will become performance per watt rather than performance alone.

To use a topical analogy, ATI is positioning itself as the fuel-efficient mid-sized sedan compared to the large, power hungry SUVs of NVIDIA. Except that unlike automobiles, if you really need the performance, you can still combine GPUs together through CrossFireX or SLI, so you can afford to start with a mainstream part, then upgrade by getting another card when the prices are inevitably lower, or when the applications or games starts to overtax the hardware. Or in other words, the GPU business is looking more like the CPU industry. And we're not talking about GPGPU.

Whether this is a viable long term strategy or just for this generation of GPUs from ATI is difficult to tell but for the consumer, they couldn't care less if this helps to lower the cost of building a gaming PC. For all the fancy marketing talk, can ATI deliver the goods this time round? We'll see that in the following pages, where we attempt to summarize some of the changes made to the Radeon HD 4800 series.



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