Let's get down with the sickness

Actions speak louder than words-Let’s get down with the sickness!

So now we’ve delved into descriptions and terms used in A64 platforms and we briefly discussed which factors alter clock speeds and how that might affect system speed and stability. Now we will discuss the practice of overclocking the Athlon64 and our goals of increasing system performance. What we need to understand is that Athlon64 system optimization is a juggling act. Up one factor, down another, increase some voltage, adjust some settings; all in an effort to glean the highest performance out of the parts we have. I cannot stress enough, that basic research into the parts you have is imperative for you to understand what you might expect in terms of their overall abilities. What I am going to do is walk you through a systematic approach to overclocking each individual area of your system to find their limits, then my method of combining these factors for overall best performance.


Exploring Max HTT Speed

Initially, I was going to first discuss finding max CPU speeds. However, I soon realized that if we are limited by our motherboard, we will be soon become frustrated and confused as to what is causing the problem. To find max HTT speed, we need to remove CPU and ram as possible limiting factors. To do this, simply down the CPU multiplier 2 whole numbers and set the ram speed to either 166 or 133 MHz. We should then lower HT/LDT multiplier to 3x and start pushing HTT bus until we have issues. If we are left with a board that will not do over 230HTT given that our CPU, memory, and Hypertransport bus speeds are all in spec, then we need to consider the board as a limiting factor and our expectations for overclocking on this platform need to be adjusted to allow for this limitation. If we have a good board though that does 300+ HTT, then we really have some room to work with and explore our CPU and Memory speeds. Some motherboards will invariably overclock better and higher than other boards. For instance, in general I would say that NForce 3 motherboards allow for higher scaling of HTT versus Via motherboard implementations. As a general rule, I will list some expectations you might hope to achieve given your platform.

NF3 150 chipset--- set AGP to 67-68 MHz to lock AGP

Set HT/LDT multiplier to 2x

Should be able to scale HTT above 275 MHz. Depending on motherboard this may be less if using SATA hard drives.

Via KT800--- Set HT multiplier to 3x

HTT can possibly scale to 220-240 MHz levels. Now AGP and PCI are not locked, so you will experience limitation in AGP card or in hard drive tolerance, often before CPU limitation is reached.

NF3-250 754 or 939 motherboards---- Set AGP to 67-68 MHz to lock AGP and PCI buses

Set HT/LDT multiplier to 3x

Should be able to reach 275-300+HTT speeds *(I have noted with some Winbond CH-5 based memories that even using ram divider, HTT bus can not be scaled past 230-240mhz).

Via KT800Pro---Set AGP/PCI lock to enable in bios if available. If not an option, refer to above KT800 recommendations

Set HT multiplier to 3x

Should be able to scale HTT to 250-270 MHz.

These levels are estimates only and meant to give you an idea of experiences that I have had or have seen others encounter. I would not be surprised if some people exceeded these estimates or fell far short. Chipset and board quality vary greatly, and choosing a high quality motherboard with overclocking options will go a long way towards promoting your overclock. That said, a little luck never hurts in getting a board that performs above the norm versus one that is a flaming pile of dung.