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Gigabyte GeForce GTX 550 Ti OC graphics card review

by Parm Mann on 15 March 2011, 13:01 3.0

Tags: Gigabyte (TPE:2376), NVIDIA (NASDAQ:NVDA)

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Introducing the GeForce GTX 550 Ti

Between the GeForce GTX 560 Ti, GTX 570 and GTX 580, NVIDIA's 500-series product range has the £200+ gaming market pretty well sewn up.

But that's merely a small fraction of the overall landscape, and while the last-generation GTS 450 and GTX 460 continue to offer good value to the sub-£150 crowd, NVIDIA's now looking to bring second-generation Fermi to the masses. It'll start that process with the new GeForce GTX 550 Ti.

Taking aim at the mainstream

Launched today, the £120 graphics card represents the next step down in the GeForce 500-series hierarchy from the £190 GTX 560 Ti, and as you might have guessed from the significant decrease in price, we're talking a fairly large step.

Built on the same tried-and-trusted 40nm process, the GTX 550 Ti is an evolution of the previous-generation's GTS 450 - both cards make use of a 238mm² die packed with 1.17 billion transistors. And the similarities run deeper than that. Both the GTS 450 and GTX 550 Ti feature a single graphics processing cluster that's made up of four 48-core streaming multiprocessors (SMs).

That's an identical 192 CUDA cores apiece, but that's roughly where the similarities end. Cast your memory back and you might recall that the GTS 450's GF106 die utilised only two of a possible three memory-controller partitions, resulting in a 256KB L2 cache, two sets of eight ROPs and a 128-bit memory interface. Thanks to improved yields and transistor-level changes, the GTX 550 Ti's revised GF116 die makes full use of all three memory-controller partitions - that means a larger 384KB L2 cache, a total of 24 ROPs and a 50 per cent wider 192-bit memory interface capable of delivering almost twice the memory bandwidth.

And the improvements don't end there. With the added efficiency of the GF116 transistors, NVIDIA's able to boost frequencies across the board. Core clock rises to 900MHz (up from 783MHz on GTS 450), shader clock is boosted to 1,800MHz (up from 1,566MHz) and the card's 1GB frame buffer runs along merrily at an effective 4,104MHz. Notice anything peculiar? The 1GB frame buffer shouldn't be possible...

A memory mystery

Armed with half-a-dozen 32-bit memory controllers, NVIDIA was faced with something of a conundrum; does it equip the GTX 550 Ti with 768MB (6 x 128MB) or 1,536MB (6 x 256MB chips) of memory. The answer is neither. In an effort to match the GTS 450's 1GB frame buffer, the manufacturer has done something a little weird - it's used mixed-density memory chips; 4 x 128MB and 2 x 256MB.

It's an approach to GPU memory we've not seen before, and NVIDIA must be confident that the mixed modules won't have a knock-on effect on latency. On paper, it has the required effect - GTX 550 Ti gets the desired 1,024MB of GDDR5 memory and sidesteps having to go into expensive-to-produce 1,536MB territory. Everyone's a winner, it seems.

Here's how all the numbers stack up:

  GTS 450
GTX 460
GTX 460
GTX 550 Ti
GTX 560 Ti
GTX 570
GTX 580
Transistors 1.17bn 1.95bn 1.95bn 1.17bn 1.95bn 3.0bn 3.0bn
Die size 238mm² 367mm² 367mm² 238mm² 367mm² 520mm² 520mm²
Fermi revision GF106 GF104 GF104 GF116 GF114 GF110 GF110
General clock 783MHz 675MHz 675MHz 900MHz 822MHz 732MHz 772MHz
Shader clock 1,566MHz 1,350MHz 1,350MHz 1,800MHz 1,645MHz 1,464MHz 1,544MHz
Memory clock  3,608MHz 3,600MHz 3,600MHz 4,104MHz 4,008MHz 3,800MHz 4,008MHz
Memory size 1,024MB GDDR5 768MB GDDR5 1,024MB GDDR5 1,024MB GDDR5 1,024MB GDDR5 1,280MB GDDR5 1,536MB GDDR5
Memory interface  128-bit 192-bit 256-bit 192-bit 256-bit 320-bit 384-bit
Memory bandwidth 57.7GB/s 86.4GB/s 115GB/s 98.5GB/s 128.3GB/s 152GB/s 192.4GB/s
SMs 4 7 7 4 8 15 16
Shaders 192 336 336 192 384 480 512
GFLOPS 601 907 907 691 1,264 1,405 1,581
L2 cache 256KB 512KB 512KB 384KB 512KB 640KB 768KB
Texturing 32ppc bilinear
32ppc FP16
56ppc bilinear
56ppc FP16
56ppc bilinear
56ppc FP16
32ppc bilinear
32ppc FP16
64ppc bilinear
64ppc FP16
60ppc bilinear
60ppc FP16
64ppc bilinear
64ppc FP16
ROPs 16 24 32 24 32 40 48
ROP rate 12.5 16.2 21.6 21.6 26.3 29.3 37.1
GTexel/s bilinear 25.1 37.8 37.8 28.8 52.7 35.1 49.4
FP16 rate 25.1 37.8 37.8 28.8 52.7 35.1 49.4
Power connectors 6-pin 6-pin + 6-pin 6-pin + 6-pin 6-pin 6-pin + 6-pin 6-pin + 6-pin 8-pin + 6-pin
Board power (TDP) 106W 160W 160W 116W 170W 219W 244W

Going strictly by the spec. sheets, GTX 550 Ti won't offer enough oomph to best last year's GTX 460, but it should easily breeze past GTS 450 - to the tune of roughly 28 per cent if NVIDIA's own calculations are anything to go by.

Better than GTS 450 but not as good as GTX 460 puts pricing in the sub-£120 region, an area that's hugely important for NVIDIA. You might hear the company describe this card as something of an Xbox killer - it's the casual, mainstream solution it's hoping you'll choose instead of a games console. Let's see if GTX 550 Ti is up to the challenge by examining a partner card from Gigabyte.