AMD Radeon HD 6990 vs ATI Radeon HD 4855
We compared two Desktop platform GPUs: 2GB VRAM Radeon HD 6990 and 512MB VRAM Radeon HD 4855 to see which GPU has better performance in key specifications, benchmark tests, power consumption, etc.
Main Differences
AMD Radeon HD 6990 's Advantages
Released 1 years and 2 months late
More VRAM (2GB vs 512GB)
Larger VRAM bandwidth (160.0GB/s vs 115.2GB/s)
896 additional rendering cores
ATI Radeon HD 4855 's Advantages
Lower TDP (110W vs 375W)
Score
Benchmark
FP32 (float)
Radeon HD 6990
+246%
2.55 TFLOPS
Radeon HD 4855
0.736 TFLOPS
Graphics Card
Mar 2011
Release Date
Jan 2010
Northern Islands
Generation
Radeon R700
Desktop
Type
Desktop
PCIe 2.0 x16
Bus Interface
PCIe 2.0 x16
Clock Speeds
-
-
-
-
-
-
1250 MHz
Memory Clock
900 MHz
Memory
2GB
Memory Size
512MB
GDDR5
Memory Type
GDDR5
256bit
Memory Bus
256bit
160.0GB/s
Bandwidth
115.2GB/s
Render Config
24
Compute Units
8
-
-
-
1536
Shading Units
640
96
TMUs
32
32
ROPs
16
-
-
-
-
-
-
8 KB (per CU)
L1 Cache
16 KB (per CU)
512 KB
L2 Cache
256 KB
-
-
-
Theoretical Performance
26.56 GPixel/s
Pixel Rate
9.200 GPixel/s
79.68 GTexel/s
Texture Rate
18.40 GTexel/s
-
-
-
2.550 TFLOPS
FP32 (float)
736.0 GFLOPS
637.4 GFLOPS
FP64 (double)
147.2 GFLOPS
Board Design
375W
TDP
110W
750 W
Suggested PSU
300 W
1x DVI
4x mini-DisplayPort 1.2
Outputs
1x DVI
1x HDMI 1.3a
1x VGA
2x 8-pin
Power Connectors
1x 6-pin
Graphics Processor
Antilles
GPU Name
RV770
Antilles XT
(215-0807027)
GPU Variant
RV770 PRO
(215-0669065)
TeraScale 3
Architecture
TeraScale
TSMC
Foundry
TSMC
40 nm
Process Size
55 nm
2.64 billion
Transistors
0.956 billion
389 mm²
Die Size
256 mm²
Graphics Features
11.2 (11_0)
DirectX
10.1 (10_1)
4.4
OpenGL
3.3
1.2
OpenCL
1.1
N/A
Vulkan
N/A
-
-
-
5.0
Shader Model
4.1
