Biostar TF8200 A2+ Motherboard
Author: Zahn Funk
Editor: Shawn Knight
Date: 06-07-2008
Provided by: Biostar
Pages:
Overclocking

When it comes to overclocking, the K10 is a little bit different than the K8 generation of chips. There are several good Phenom overclocking guides on the internet, but I will cover the basics as part of this review.

K8 and K10 processors both start with a base frequency of 200Mhz. This is used to calculate every other frequency that the various components run at, so it's important to remember that increasing this base number will overclock the processor, memory and the bus!


To determine the speed that the processor runs at, both K8 and K10 use a CPU multiplier, often referred to as Frequency ID or FID in the BIOS. This multi times the base frequency gives you the CPU speed. In K8, the integrated memory controller or northbridge runs at the same speed as the processor. In K10, the NB speed is determined separately by use of a NB multiplier. So as you can see above, the NB also has a FID value. There is also a VID to set the base voltage for both, then additional voltage can be added through the BIOS Over-Voltage screen. Finally, K10 adds a DID or divider to the multi. Since the multi is available in half steps, using a divider of two for example can reduce this to quarter steps. Therefore it is possible to fine tune the speed to a very precise amount if desired. There should also be a DID for the NB, however this appears to be absent in the TF8200 BIOS. But considering that this sub-menu wasn't even present in the BIOS release the board shipped with, I guess I can't complain too much.


In addition to the CPU and NB speeds, the HyperTransport or HT speed is also calculated from the base frequency. In K8, we had choices of 1x, 2x, 3x, 4x or 5x for a maximum factory speed of 1000Mhz. In K10, the multipliers go all the way up to 13x or 2600Mhz. However one very important note is that the HT speed can never be more than the NB speed. The TF8200 BIOS will not allow you to set a value higher than the NB. So with the 9850 Phenom chip, which has a stock NB frequency of 2000Mhz, the HT multiplier is also limited to 10x, giving a resulting value of 2000Mhz as well. Rather than the multipliers being listed as 1x, 2x, 3x, etc. in the BIOS, the options are given by resulting speed, ie. 200, 400, 600, etc. Again, it is important to remember that just because you set a value of 2000Mhz for the HT speed, this value is not "locked" at 2000Mhz if the base frequency is increased.

When selecting memory speed, K8 used a wide variety of dividers based on which CPU multiplier you were using, and it was possible you might not get the rated speed out of your memory if left at default settings. For example, selecting DDR2-800 in the BIOS did not mean it ran at 400Mhz if the processor used an odd-numbered multiplier. K10 has resolved that whole issue by fixing the memory ratios so that they aren't affected by the CPU multiplier. However, as I mentioned before, selecting 533Mhz or the 3/8 memory ratio may limit your timing options available. In the TF8200, when setting the memory value to 533 in the BIOS, the CAS, TRCD, TRP and TRAS values are limited to a minimum of 5-5-5-15. While it is true that most DDR2-1066 memory calls for these timings at that speed, if you happen to have some sticks that will actually run faster with more voltage, you will not be able to lower those in the BIOS. In such a case it may be better if you use the 400 memory frequency instead, and then overclock it by increasing the base frequency.


Using the 9850 Phenom processor and OCZ DDR2-1066, I was able to achieve a decent overclock of 500Mhz on the CPU. It did require increasing the CPU voltage from the stock 1.3v to 1.475v. As can be seen in the above CPUz screenshot, the 3000Mhz speed was achieved using a base frequency of 250 with a 12x CPU multiplier, and a NB and HT multi of 8x, keeping both at a stock 2000Mhz speed. The memory is running in dual-channel mode, unganged, which means the memory controller is addressing the DIMMs in 2x64bit mode instead of 1x128bit. The memory ratio is set to 400 or 1:2 ratio, which nets an overall speed of 500Mhz or DDR2-1000, at reduced timings of 4-4-4-8 with 2.4v.


In addition to overclocking through the BIOS, Biostar includes their TSeries Overclock3 utility that allows some manipulation from within the OS. The four main voltages can be changed or the CPU base frequency setting adjusted, and then a short test run to verify the settings. The nice thing is that this is much easier and less confusing to users who may not be used to BIOS overclocking. The bad part is that you are extremely limited as to what you can change and if the machine locks up or the test run fails, the system is automatically rebooted and the CMOS cleared, so make sure to have a recently saved backup of your settings!


Another utility found on the software CD is the Hardware Monitor, which provides an easy-to-read voltage, temperature and CPU speed/utilization display. There are many other such utilities available and it's really up to user preference over which one to use, however it's nice that Biostar includes this tool.

On to final thoughts and conclusion.


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