Overclocking the TNT

Two types of TNT

The Canopus Spectra 2500 which was used in the original TNT Overclocking tests featured 16MB of Hyundai SDRAM running at 110MHz.   The test card AnandTech used wouldn't reliably accept any memory clock speeds greater than 115MHz, a fairly limiting factor in removing the bottleneck recently set before us. 

An interesting thing to note is that the Creative Labs and STB TNT cards don't use the same Hyundai SDRAM Canopus seems to be shipping with their Spectra 2500.  Instead they use Fujitsu SDRAM which seems to have a better time overclocking, in fact, the Creative Labs Graphics Blaster TNT AnandTech just recently started testing would allow for its memory to be taken up to 130MHz without nearly as many crashes as the Spectra 2500 experienced at 120MHz. 

Canopus either chose to go with the cheaper SDRAM to keep the costs of their luxurious TNT card down to a competitive level, or has yet to experiment in the Fujitsu arena.  Either way, it looks like that alone takes Canopus out of the running for the most overclocking friendly TNT board. 

Cooling the TNT

Here's the big question, how did Anand do it?   Unfortunately the specifics of the cooling system used cannot be disclosed at this time, however the chip itself was cooled to below the freezing point.  Since we've managed to eliminate the Spectra 2500 as a possibility for the true overclocker's test, how do we get the Graphics Blaster TNT and STB Velocity 4400 to run at higher clock speeds without the cool fan Canopus outfitted their TNT with? 

Fortunately, the heatsinks used on the CL and STB cards is quite reminiscent of the older 486 heatsinks.  Low and behold, a quick trip out to Radio Shack for a 486 fan will reveal that virtually any small fan will easily attach to either of those two cards.  Considering that the Creative Labs card sells for $169 retail, an extra $7 can bring you one step closer to the $199 Canopus Spectra 2500 without too much of the added cost. 

AnandTech is still working on feasibility tests for the cooling idea, however as of now the outlook doesn't look too incredibly promising.  More information about the cooling methods will be disclosed at a later point in time.

The Difference is at 1024 x 768

Each test run performed at an overclocked clock speed with the Riva TNT must be monitored carefully as much instability can result from a single mistake in the setup process.  An individual test can sometimes take up to three or four runs to complete properly due to a number of outside factors, this complexity limits the amount of tests than can be run at a given time.  For this reason, the original article only featured benchmarks at 800 x 600.  Logically, one would assume that increasing the resolution to 1024 x 768 would produce a greater increase in performance over the default clock speed in comparison to the increases seen at 800 x 600.  Following up that statement with benchmarks proved just that, the increase from 90 to 120MHz at 800 x 600 proved to be 19% while at 1024 x 768 the increase was 23% showing the trend towards producing a chipset that can up the resolution recommendation to 1024 x 768.  Once the TNT makes it out at 125MHz, regardless of the speed of the memory, you can expect it to be a fairly decent performer at 1024 x 768 on most of the mid-range processors as well as an excellent companion for high-end processors at that resolution. 

5MHz Can Make a Difference

Since the Graphics Blaster TNT was still under initial evaluation at the time of the follow-up to the TNT article, it couldn't be used for the benchmarks, however as the Canopus Spectra has been able to show us, a 5MHz increase in memory clock does make a noticeable difference in overall overclocked performance.  The 5% increase in clock speed results in an increase in performance of about 3 - 4%, judging by this one would be led to assume that running the SDRAM at a greater frequency (130MHz for example) would yield a much higher overall performance increase, possibly bringing us one step closer to that desired Voodoo2 SLI performance.   For those results however, we'll have to wait for the Creative Labs TNT Review which is nearing it's completion as this article is being written.

So once again, armed with the Canopus Spectra 2500, and the AnandTech cooling system, let's put the chip to the test as the TNT is overclocked once again for an even greater trial of its true power.