Introduction

GeForce 6600 GT: Taking the mainstream market by storm

NVIDIA’s GeForce 6600 GT is taking the mainstream segment of the graphics market by storm right now. By taking the same fundamental technology found in the GeForce 6800 series and migrating it down to a more tangible price point, NVIDIA has struck a real chord with users. Sure, the GeForce 6600 GT features half the number of pixel/vertex units, and only a 128-bit memory controller, but thanks to its blazing clock speeds, this is more than enough to outperform last year’s high-end graphics card, the $500 RADEON 9800 XT, in many cases.

The only downside to GeForce 6600 GT had been the lack of AGP offerings; NVIDIA initially launched the GeForce 6600 in PCI Express form only. Up to this point, PCI Express hasn’t taken off as quickly as many had expected. The only PCI Express-capable motherboards on the market that have been released are all based on Intel’s 925 and 915 chipsets, which, quite frankly aren’t popular solutions among enthusiasts. Neither chipset offers much of a performance improvement over Intel’s older 875P and 865PE chipsets, and the added features such as improved audio and Serial ATA support haven’t really helped to sell more motherboards either. Of course, it’s also a pretty well known fact that Athlon 64 is currently outperforming Pentium 4 in most games right now.

The bottom line is that PCI Express systems haven’t displaced AGP rigs yet, and there is still a large chunk of gamers with AGP systems who would like to upgrade their current DX8 graphics card to something faster.

Realizing this, NVIDIA quickly adapted their GeForce 6600 for the AGP market. By taking their high speed interconnect (HSI) chip, and grafting it to GeForce 6600, NVIDIA had their solution months before the competition, and just in time for the holiday shopping season. The HSI chip acts as a translator of sorts, allowing PCI Express chips to “talk” with AGP components and vice versa. HSI was first used on NVIDIA’s GeForce PCX series, which were GeForce FX cards that were adapted for PCI Express thanks to HSI. For GeForce 6600 GT AGP, HSI works in the other direction, translating the PCI Express protocol for use with AGP chipsets such as nForce2/3 and Intel 865/875P. An aluminum heatsink is then used to help keep the HSI chip cool.

Besides the addition of the HSI chip, the second physical difference you’ll notice on GeForce 6600 GT AGP boards in comparison to their PCI Express-based cousins is the presence of a 4-pin Molex power connector on the back of the card. Unlike PCI Express, the AGP interface doesn’t have quite enough juice to supply the GeForce 6600 GT’s NV43 GPU with enough native power, an external source is required to run the card at full clocks (if the Molex power connection isn’t used, the core underclocks itself to 300MHz).

The final difference between PCI Express GeForce 6600 GTs and their AGP equivalent lies in the memory clock frequency. While the graphics core in both cards runs at 500MHz, NVIDIA’s reference specifications for the GeForce 6600 GT AGP only call for a memory frequency of 450MHz (900MHz effective). This is 50MHz below the memory clock speed of the GeForce 6600 GT PCI Express, giving it a slight edge over AGP-based 6600 GT cards. Some card manufacturers (BFG, XFX) in this article have decided to go beyond NVIDIA’s reference specifications for the GeForce 6600 GT however. Let’s go over the feature set of each of the cards…

The GeForce 6600 GT cards compared
Card	Temp Monitoring	Core Clock (MHz)	Memory Clock (MHz)	VIVO	Noise Level	HDTV output	Dual DVI
ASUS N6600 GT	Yes	500	450	No	2	No	No
BFG GeForce 6600 GT OC	Yes	525	525	No	4	Yes	Yes
eVGA e-GeForce 6600 GT	No	500	450	No	5	Yes	No
Leadtek WinFast A6600 GT TDH	Yes	500	450	No	3	Yes	No
MSI NX6600 GT	No	500	450	Yes	1	Yes	No
XFX GeForce 6600 GT	Yes	500	500	No	5	No	Yes