Specifications

While rumors suggested that the Radeon 5700’s “Juniper” graphics core could support as many as 1120 stream processors and a 192-bit memory interface, unfortunately those rumors were untrue. Instead what ATI has essentially done is much simpler than that: take a Radeon 5870, slice it in half, and you’ve got a Radeon 5770. Take a 5850, slice it in half, and you’ve got a Radeon 5750.

As a result, the 5770 is equipped with 800 stream processors and 128-bit GDDR5 memory interface, while the 5750 gets by with 720 stream processors and also utilizes a 128-bit GDDR5 memory interface:

Radeon 5800 vs 5700 Series Comparison
	ATI Radeon 5750	ATI Radeon 5770	ATI Radeon 5850	ATI Radeon 5870
Manufacturing Process	40-nm	40-nm	40-nm	40-nm
# of Transistors	1.04 billion	1.04 billion	2.15 billion	2.15 billion
Die Size	166mm2	166mm2	334 mm2	334 mm2
# of Stream Processors	720	800	1440	1600
# of Texture Units	36	40	72	80
# of ROPs	16	16	32	32
Memory Type	GDDR5	GDDR5	GDDR5	GDDR5
Memory Interface	128-bit	128-bit	256-bit	256-bit
Max Board Power	86W	108W	151W	188W
Idle Board Power	16W	18W	27W	27W

Those of you who were hoping for more shaders and a wider memory interface are likely going to be pretty disappointed by this at first, but thanks to high clock speeds, the 5700 series cards are still able to deliver more shading and texturing horsepower than ATI’s primary performance GPUs from last year, the Radeon 4850 and 4870:

Radeon 5700 vs Radeon 4800 Comparison
	Radeon 4770	Radeon 4850	Radeon 4870	Radeon 5750	Radeon 5770
Manufacturing Process	40-nm	55-nm	55-nm	40-nm	40-nm
# of Transistors	826 million	956 million	956 million	1.04 billion	1.04 billion
Core Clock Speed	750MHz	625MHz	750MHz	700MHz	850MHz
# of Stream Processors	640	800	800	720	800
Compute Performance	960 GFLOPS	1.0 TFLOPS	1.2 TFLOPS	1.008 TFLOPS	1.36 TFLOPS
Texture Units	32	40	40	36	40
Texture Fillrate	24 GTexels/sec	25 GTexels/sec	30 GTexels/sec	25.2 GTexels/sec	34 GTexels/sec
ROPs	16	16	16	16	16
Pixel Fillrate	12 GPixels/sec	10 GPixels/sec	12 GPixels/sec	11.2 GPixels/sec	13.6GPixels/sec
Z Fillrate	48 GSamples/sec	40 GSamples/sec	48 GSamples/sec	44.8 GSamples/sec	54.4 GSamples/sec
Memory Clock Interface/Type	128-bit GDDR5	256-bit GDDR3	256-bit GDDR5	128-bit GDDR5	128-bit GDDR5
Memory Clock Speed	800MHz (3.2Gbps data rate)	1000MHz (2.0Gbps data rate)	900MHz (3.6Gbps data rate)	1150MHz (4.6Gbps data rate)	1200MHz 4.8Gbps data rate)
Memory Bandwidth	51.2GB/sec	64GB/sec	115.2 GB/sec	73.6GB/sec	76.8GB/sec
Max Board Power	80W	110W	160W	86W	108W

As you can see in the chart above, ATI uses the same basic structure as RV770, with 10 SIMD cores for the 5770 and one texture unit per SIMD core. ATI disables one SIMD core for the Radeon 5750, leaving 720 active stream processors and 36 texture units.

Thanks to their high clock speeds, Radeon 5750 and 5770 compare well against the 4850 and 4870 in many aspects; the Radeon 5750 clearly outclasses the Radeon 4850 while also needing less power. The Radeon 5770 only falls short to the 4870 in memory bandwidth, where it’s limited to 76.8GB/sec of peak bandwidth versus the 4870’s 115.2GB/sec. That’s a difference of exactly 1.5X more bandwidth in favor of the Radeon 4870.

As such, the Radeon 5770 isn’t going to be able to keep up with the Radeon 4870 under any moderate or high resolutions, especially if you crank up the AA, but ATI’s banking on the 5770’s DX11 feature set to make up the difference.


As we’ve stated previously, besides potentially delivering improved image quality, game developers can leverage DX11 to also improve performance, this could potentially be used to close part of the gap separating the 5770 from the 4870. Now obviously this won’t help the 5770 perform any better than the 4870 with today’s DX9 and DX10 games, but it could play dividends down the road as more DX11 apps appear.

The Radeon 5700 cards completely outclass ATI’s previous mainstream GPU, the Radeon 4770.