Overclocking the AMD 1055T – 3700mhz out of the box

Rating: 8.0.

The latest AMD 1055T and 1090T six core processors are fantastic value for money and we particularly like the 1055T due to the very low asking price of around £160 inc vat. Many people opt for the 1090T Black Edition due to the unlocked Multipler and higher clock speed (3200MHz – 400MHz difference), but what if we were to tell you that almost all 1055Ts can hit 3,700mhz with no extra voltage and just a little BIOS knowledge?

We have had access to five 1055T samples now and all of them can hit 3,700MHz with just a little BIOS tweaking. Sure it is slightly more tricky to achieve than with the unlocked Black Edition, but its still quite possible and we will show you how to do it in a step by step article today.

Is this really worth the effort? Sure it is, if you are buying a new system and want Black Edition performance, this could save you around £80-90 allowing you to basically fund the purchase of a new Sapphire HD5670 Ultimate Edition graphics card, one of our favourites at KitGuru. You should also be ending up with higher performance than the more expensive reference clocked 1090T Black Edition.

The purposes of this little guide today isn't to detail how to push every 1055T to the limit, but to actually show you how your sample should reach 3700Mhz without any voltage increases whatsoever. As with every overclocking experience there is a certain chance your system will become unstable requiring default values to be reloaded but as we aren't increasing voltages, its pretty much as safe as it gets.

If you are completely new to overclocking we will try and get under the skin of this as simply as possible to not only help you get more from your AMD processor but so you can understand what you are doing.

Raising a processor clock frequency means it operates faster and how we achieve this is basically the same with every CPU on the market. All processors have their frequency represented as a clock multiplier, which is multiplied by a base frequency. These base frequencies will vary from chip to chip but with the 1055T this multipler is locked to 14. The 1090T is a ‘Black Edition' processor which means this primary clock multiplier is unlocked and you can raise it by simply changing it in the bios – this is a part of the extra cost however. We need to take a different approach with the 1055T and raise the base frequency. Don't start sweating this is not complex and today I will show you how to overclock your 1055T by doing this. How does this work if the CPU is locked? Well this clock generator is located on the mainboard itself and not inside the CPU, this can't be blocked.

The biggest issue with overclocking via a base frequency methodology is that this is not only connected to the clock frequency of the processor but to memory bus frequency, L3 cache frequency and the frequency of the bus between the core logic set and the actual chip. Therefore when you increase this base clock you are increasing sub-system speeds also. If you have already overclocked an AM3 dual or quad core CPU then this is the same principle but for a new user to this platform it can be confusing. It is also worth pointing out that with the launch of the Phenom II X6 AMD have introduced Turbo Core Technology, based on a similar principle to Intels.

When breaking apart the overclocking algorithms with AMD we have five main categories.

• CPU Clock frequency. This is the main parameter which is directly related to the processor installed. The 1055T operates at 2800mhz.
• Turbo Mode Frequency. This is the CPU speed when under partial load. The Phenom II X6 sets this frequency when half (or more) of the cores are idle. This can help to improve performance in specific situations.
• Hypertransport bus frequency. This is the bus which connects the processor with the core logic set. The 1055T Phenom II X6 processor has this set to 2.0ghz by default.
• Memory Frequency. This is the memory sub system frequency which is connected to the modules installed, they can be 800, 1067, 1333 and 1600mhz.
• Frequency of the North Bridge – integrated into the CPU. This last one is the frequency of the L3 cache which in integrated into the processor and it also relates to the frequency of the memory controller. This is set to 2.0ghz.

All of these multipliers are independently configured and are easily adjusted in the motherboard bios. One point worth making early on is that the Hypertransport speed should never be clocked higher than the frequency of the North Bridge which is integrated into the CPU.

For this article we are using the excellent MSI 890 GXM-G65 with the latest V1.6 bios – dated 2010-04-30. We have achieved the same results with several motherboards so we are confident in saying that this should be easily replicated on a variety of systems. We are using 8GB of Kingston DDR3 1600mhz memory which we reviewed before over here.  As we aren't forcing high core voltage you don't need the most expensive cooling on the market, but something like the Thermaltake Contac 29 we reviewed recently is an inexpensive yet very effective option to aim for.

The image above shows the default clock speeds of the processor, out of the box and we are going to run Cinebench 11.5 to show you the reference performance values of this specific system.

The default score is 4.91 points which is a pretty good result – related to the six core performance of the 1055T.

Next, let us reboot and have a look at the bios settings. If you don't know how to get into your bios, then consult your motherboard manual, but you normally get a few seconds to read your specific motherboard overview on boot up. Generally F2 or the Delete Key are used.

With this MSI motherboard we need to access the “Cell Menu” seen above, this is where all the overclocking parameters are configured. The CPU info image also shows the CPU ratio which we know is 14. This is tied into the frequency of 200 to give a 2800mhz CPU clock speed (14×200).

On many bioses the CPU ratio will show AUTO (above) but it will be defaulting to 14.0. You can't adjust this higher so just leave it or manually set it to 14.0 to keep yourself right.

The “Adjust CPU FSB frequency (MHz)” (sometimes labelled “CPU Bus Frequency”) is the main setting we will be using to get higher clocks from the CPU. Also disable AMD Turbo Core Technology, it will play havoc with the system when we get to the higher overclocks.

Scrolling down in our Cell Menu bios area you can see the FSB/DRAM ratio is set to auto which shows 1333mhz. We can manually adjust this to 1600mhz, however as we are going to be overclocking with CPU FSB frequency shortly this will also increase … we will leave it as is, for now. If you are using lower speed memory be aware you may need to adjust the settings to keep it within specification.

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