Radeon HD 2400 XT Reference Board Examination
In contrast to HD 2600 XT, HD 2400 XT is a curious mix of regular- and low-profile PCB. The tiny RV610 GPU barely needs actively cooling, so it's a shame to see an active cooler on the reference hardware. It's further a shame to report that at full speed the noise from the cooler is obnoxious enough to wonder what the hell is going on inside your PC. The good thing is that it's like HD 2600 XT in that it's nicely controlled in terms of speed adjust and that you'll probably never hear it at full tilt. We never did through all of our testing.
Display output wise it's somewhat disappointing to see analogue VGA instead of another DVI port, but we can sort of see why given the target market for the product. Still, the pennies saved by not shipping a DVI-to-VGA convertor in the box because it's on the backplane shouldn't be, we argue.
You can clearly see the traces from the Crossfire connectors snake across the tract of full-height PCB near the backplane, around space for a Rage Theater ASIC which isn't filled. The DRAMs are 512Mib each, rated to 900MHz (but run at 800MHz on the 2400 XT). Given that there's 4, that's 256MiB in total for the framebuffer, like the HD 2600 XT on the previous page, and pairs share the 64-bit external interface.
Run the numbers and you get memory bandwidth at 12.8GB/sec, 350Mtris/sec (700MHz GPU clock, half a tri per clock), and a peak scalar instruction rate of 28Ginst/sec (40 * 700). Pixel throughput is 2800Mpixels/sec by virtue of the single quad ROP pipe at the end of the chip. Consumer graphics chips enjoyed more than 3Gpixels/sec of final throughput 5 years ago, but we digress and drown in a sea of complaints about flops-per-pixel.
We expect HD 2400 XTs to be passively cooled before you can say, "BUT MY MEDIA CENTER YOU FOOLS, SOMEONE HAS TO THINK OF MY SILENCE!", and I'd love a pair for my box that are passively cooled and have two DVI outputs. The first vendor to oblige gets my money.
