NVIDIA’s TurboCache

NVIDIA’s TurboCache technology is used with the NV44 core in GeForce 6200TC graphics cards. GeForce 6200TC cards, like RADEON X300SE cards, feature four pixel pipelines, but have a 350MHz core and various memory speeds. There are actually four different versions of NVIDIA’s GeForce 6200TC, one with a 32-bit memory bus and 16MB onboard memory, a second SKU with a 32-bit memory bus but with twice the amount of memory (32MB) onboard, and two different SKUs with a 64-bit memory interface.

We’ve summarized all the TurboCache configurations in the following table:

GeForce 6200 TurboCache Configurations
Card	Core Clock Speed (MHz)	Memory Clock Speed (MHz)	Onboard Memory Size	Width of Memory Interface	Peak Onboard Memory Bandwidth
GeForce 6200 TurboCache 128MB	350	350	16	32	2.8
GeForce 6200 TurboCache 128MB	350	275	32	32	2.2
GeFore 6200 TurboCache 128MB	350	350	32	64	5.6
GeForce 6200 TurboCache 256MB	350	275	64	64	4.4

TurboCache works in a similar manner to HyperMemory, working an onboard memory management unit to dynamically determine the amount of system memory to be used as frame buffer memory. Once the system memory is used as graphics memory, it can then revert back to standard system memory. Essentially, TurboCache is on “On-Demand” memory service, borrowing system memory for graphics frame buffer as needed.

However even though TurboCache can write directly to system memory, a minimum local memory requirement of 16MB at 350MHz is required. This memory must have a clock speed of at least 350MHz and with TurboCache, like HyperMemory, an additional 128MB of system memory can be used as graphics frame buffer memory.


This is where the fast, bidirectional bandwidth of PCI Express comes in, and when the 8GBps bandwidth of PCI Express is coupled with the 2.8GBps bandwidth of local memory, the effective bandwidth of a GeForce 6200TC GPU is up to 13.6GB/sec.


Today we’ll be taking a look at two different versions of the GeForce 6200TC, the XFX GeForce 6200TC 128MB, with a 32-bit memory bus and 32MB of local memory, and the Leadtek GeFroce 6200TC 256MB, also featuring a 32-bit memory bus, but with 64MB of local graphics memory.


It’s important to note that unlike the RADEON X300 SE, the GeForce 6200TC has full support for Shader Model 3.0. In order to reduce manufacturing costs however, NVIDIA has removed the color and z-compression components, as well as the OpenEXR HDR found in the GeForce 6800 from the GeForce 6200 TurboCache. This will hamper the 6200 TC’s anti-aliasing performance and prevents the card from supporting high dynamic range lighting, but the card lacks the bandwidth to run with high levels of AA with good frame rates anyway, and we’ve seen the performance impact OpenEXR HDR brings in Far Cry.

Intel’s 945G

Intel’s market leadership stems from their integrated graphics platforms, the 865G and 915G being widely adopted by OEM’s and consumers alike in recent years. With the coming of dual-core CPU’s, Intel recently announced their new 945G platform, with a new and upgraded integrated graphics core. This core, the GMA 950, will compete directly with NVIDIA and ATI’s new low-end offerings for market share and wide spread adoption.

The GMA 950 is a 400MHz part that like the 6200TC and RADEON X300 SE, features four pixel pipelines. It has full support for Shader Model 2.0 and Direct X 9.0 like the RADEON X300 SE, but of course has no local memory, so it dedicates a portion of your system memory as it’s frame buffer. Motherboards featuring the 945G chipset currently are selling for as low as $110.