The 55nm RV770 is one of the best arrows in AMD’s GPU quiver, so it’s a good thing the part has proven to be both versatile and powerful. As deployed in the Radeon HD 4870, the RV770 has a full complement of 800 stream processors—just like the Radeon HD 4850—but in this design, the GPU is paired with GDDR5 memory.
GDDR5 memory boasts a very high data rate (ranging from 3.6Gb/s to 6.0Gb/s, compared to GDDR3’s 1.0Gb/s to 2GB/s). This enables AMD to deliver nearly the same memory bandwidth through a relatively narrow and inexpensive 256-bit bus as it would with a much wider and costlier 512-bit bus.
HIS put two dual-link DVI ports and an S-Video output on the mountin bracket; you'll need a DVI-to-HDMI adapter to connect to a digital home-theater system.
High-end Radeon HD 4870 cards feature 1GB of GDDR5, but HIS’s budget-oriented model is outfitted with 512MB. That might leave you a little constrained, as game developers have come to expect that gamers will own videocards with large frame buffers. Nonetheless, as you can see from our benchmarks, a halved memory allotment didn’t cause undue punishment in the games we tested.
This card is priced $20 higher than the EVGA GeForce GTX 260, but delivers far better performance in Far Cry 2 and Crysis. It also came within spitting distance of our top budget performer, EVGA’s GeForce GTX 275, which costs $30 more.
The RV770 tends to run hot at high clock speeds, but HIS’s IceQ 4+ heatsink/fan design keeps temperatures manageable without polluting your environment with noise. This chip has never exhibited a great deal of headroom for overclocking, but HIS managed to squeeze out a few extra cycles: The core runs at 780MHz (compared to 750MHz stock) while the memory hums along at 1,000MHz (compared to 900MHz stock).
Finally, if you enjoy a bit of bling inside your PC, you’ll dig this card, as the plastic shroud over the cooler reacts to ultraviolet light. Install a cold-cathode UV light in your case, and the entire shroud will emit a deep blue glow.