Radeon HD 5450 (Cedar) review: The ideal HTPC DirectX 11 graphics card?

Cedar, the latest offspring of Ati's Evergreen family, has officially been launched. The Radeon HD 5450 brings features like DirectX 11 or Eyefinity - the Cedar can handle up to three displays - to the price level below 50 Euros. But can the card deliver enough power to make use of those technologies? PC Games Hardware does the test. For all those you want to know more about the Evergreen graphics cards we have listed the appropriate reviews:

• Test Radeon HD 5970 (Hemlock)
• Test Radeon HD 5870 (Cypress XT)
• Test Radeon HD 5850 (Cypress LE)
• Test Radeon HD 5770 (Juniper XT)
• Test Radeon HD 5670 (Redwood)

Radeon HD 5450 reviewed: Specifications
The Cedar offers 292 million transistors on 62.5 square millimeters (measured by PCGH). For comparison: The bigger Redwood (HD 5670) comes with 627 million transistors. Thus the Cedar has a lot less calculation units than its siblings. Only 80 ALUs (Stream Processors) and 8 Texture Units (TMUs) feed the 64 Bit interface with data. According to the specifications the interface is linked to DDR3 memory (no G tag) with up to 800 MHz - the result is a data throughput of 12.8 GByte per second. Up to this point the Cedar matches with the older RV710 (Radeon HD 4550) - at least as long as architectural fineness or the GPU frequency are not taken into account: The HD 4550 runs at 600 MHz while the HD 5450 runs at 650 MHz.

A certain detail, which is important to understand the benchmark results, is related to the GPU architecture. Radeon GPUs up to the RV70 (HD 4890) handle the texture address interpolation with the texture units. On the Evergreen chips of the HD 5000 series this task is done by the Shader ALUs. The reason: There are a lot more ALUs than TMUs and the Stream Processors are faster, too. Cedar also follows this principle although it has only half as much calculation units per texture unit.

In other words: The 80 ALUs of the HD 5450 don't only have to deal with the Shading, but also with the texture interpolation, while the 80 ALUs of the HD 4550 only have to handle their traditional task. The benchmarks on the next page reveal the result of this situation: The predecessor graphics card is slightly faster regardless of the higher frequency of the new model.


Radeon HD 5450 reviewed: Board and Cooling
The Radeon HD 5450 is a low profile graphics card which overlaps the PCI Express slot by only 6 centimeters. This applies to AMD's reference design as well as the first partner cards that have already been announced. All the information delivered below is referring to the Sapphire Radeon HD 5450 which we used for our tests.

The board, which is only 168 millimeters short, offers a Displayport and a Dual-Link DVI connector. VGA/Sub-D can be upgraded with a full sized slot cover. Fortunately there are no moving parts and the GPU only needs a small aluminum block for cooling. Memory and chip each have a single phase for power supply and given the TDP of only 19 watt an additional power connector is not required.

The four 128 MiByte memory modules come from Samsung. As already mentioned the VRAM is running at 800 MHz - the access time of 1.2 nanoseconds would allow 833 MHz in theory.

Radeon HD 5450 reviewed: Power Consumption and Loudness
With our equipment we record the acoustic pressure in Decibel (a) and the loudness in Sone at a distance of 50 centimeters. The remaining components of our test system are silent: A AMD Athlon X2 BE 2350 with 2.1 GHz is passively cooled by a Scythe Orochi on a Asrock A780 FDP with AMD 780G chipset. The system is powered by a Nesteq X Zero PSU with 600 watt output and the operating system is stored on a Hama SSD. The ambient noise of our sound lab doesn't exceed 0.1 Sone.

The temperatures and the power consumption are also tested with this test system. We record 2D results on the Windows desktop as well as results at full workload. For this we use Race Driver Grid at 1,920 x 1,200 with 4x MSAA and 16:1 AF. The game is more challenging for the graphics card than Crysis Warhead and other games with a constant workload.

As an absolute worst-case scenario we use Ozone3D Furmark in version 1.6.5. With a renamed exe file this tool stresses the graphics cards to the maximum and is most challenging for the cooling solutions. Important: This scenario reveals what the absolute worst-case is in matters of loudness and power consumption. Such results are most unlikely to be reached during all day usage.

Radeon HD 5450 results
The Radeon HD 5450 is able to convince in both matters - power consumption and loudness. Due to the passive cooling solution there is practically no noise. And the power consumption is extremely low, too: Only 16.4 watt in Furmark and 14.5 watt in Race Driver: Grid are new top results.



Radeon HD 5450 reviewed: Overclocking
Our sample of the Sapphire Radeon HD 5450 with 512 MiByte memory can reach up to 780/1000 MHz which is an increase of 20 (GPU) respectively 25 percent (VRAM). This results in an performance advantage of up to 21 percent. Please bear in mind that every single graphics card has its individual overclocking capabilities.