Temperatures and overclocking
Temperature musings
We perform our testing on an open test bed with a 120mm fan simulating case airflow.
| Graphics cards | Sapphire TOXIC Radeon HD 4850 512MiB | Sapphire Radeon HD 4850 512MiB | Sapphire Radeon HD 487, 512MiB | NVIDIA GeForce 9800 GTX+ 512MiB | BFG GeForce 9800 GTX 512MiB | XFX GeForce GTX 260 896MiB |
|---|---|---|---|---|---|---|
| Ambient temperature | 22°C | 21°C | 25°C | 23.5°C | 21.5°C | 24°C |
| Idle temperature | 41°C | 71°C | 71°C | 53°C | 52.5°C | 48°C |
| Load temperature | 65°C | 81°C | 83°C | 67°C | 67°C | 72°C |
| Ambient-to-load delta | 43°C | 60°C | 58°C | 44°C | 45.5°C | 48°C |
Confirmation that the ZALMAN cooler beats the pants off the reference card's, providing under-load temps of some 16°C cooler, and also being quieter when doing so. This is one part we can't take into account the HEXUS.bang4buck on the previous page.
Overclocking
Sapphire's clearly using better-than-average yields and slapping RAMsinks and a big-ass ZALMAN cooler on top, so it would have been rude not to overclock the card.We managed to crank the core and shaders to a Radeon HD 4870-matching 750MHz, up from the 675MHz pre-applied to the card. Even better, the memory was stable at a lofty 2,600MHz. Compare this with the 685MHz/685MHz/2,060MHz we managed from the reference card and you'll appreciate just how potent the TOXIC is.
Looking back at the ET:QW test at 1,920x1,200 we see that the stock-clocked card scored at average 51.57fps. This rose to 56.67fps (9.9 per cent increase) when run with the pre-set TOXIC clocks, and right up to 67.3fps with the 750MHz/750MHz/2,600MHz settings, which are surprisingly close to stock Radeon HD 4870 levels.
Knowing what we now know, we're adamant that Sapphire could push the shipping clocks higher, say, to 700MHz/2,300MHz.
