If you have already read our coverage of the Radeon HD 5800 series launch, then the block diagram below should look somewhat familiar to you. As we've already mentioned, the new Radeon HD 5450 offers virtually all of the same features of 5800 series; the differences being that the 5450 series is equipped with fewer SIMD engines, and hence fewer stream processors, fewer texture units, and ROPs and it has a narrower external memory interface.
Radeon HD 5450 GPU Block Diagram
Specifically, the Radeon HD 5450 series GPU offers 1 SIMD engine with 80 total Stream Processing Units, 8 Texture Units, and 4 ROPs with a 128-bit GDDR3/2 memory interface. The actual GPU is manufactured using TSMC's 40nm process and is comprised of approximately 292 million transistors.
The Radeon HD 5450 we'll be featuring in this article is the 512MB, passively cooled version, pictured above. It is a half-height card that features a relatively large heatsink that cools the GPU and RAM mounted on the front. Please note that the heatsink does encroach on an adjacent slot, so this card should be considered dual-slot. Typical idle board power is only 6.4w with peak power of around 19.1w, so there is no need for supplemental power connectors here--the 75w offered by a PCIe slot will do. The reference specifications call for a 650MHz GPU clock, with 800MHz memory, for an effective data rate of 1.6Gbps. At those clocks, the Radeon HD 5450 offers a peak texture fillrate of 5.2GTexel/s, 2.6GPixels/s, with 12.8GB/s of memory bandwidth and up to 104 GLOPS of compute performance. We should point out, however, AMD has authorized board partners to offer overclocked boards with memory clocked as high as 900MHz--and this reference card featured a 900MHz memory clock.
The outputs on the Radeon HD 5450 consist of a dual-link DVI output, a DisplayPort output, and a standard VGA output. Any combination of these ports can be used simultaneously. The card also fully supports 'ATI Eyefinity multi-display technology, with up to three displays.
The backside of the Radeon HD 5450 is exposed, but other than the myriad of surface mounted jellybean components, there isn't much to see. The GPU heatsink retention bracket is visible right about in the center the PCB, but where the card's CrossFire edge connectors are supposed to be there are none. It is up to board partners though, whether or not to outfit their cards with CF connectors, but we doubt that will happen given the card's 3D performance. Please note, that CrossFire is still supported with two of the cards pictured here; transactions will be sent over the PCIe interface, however, instead of the CrossFire bridge.