MSI 790FX-GD70 AM3 Motherboard Review

Overclocking Results

First and foremost, if you are completely new to Phenom II overclocking we highly recommend that you check out our article on the subject, aptly titled "Hardware Canucks: Benchmarkers Guide to the Phenom II". Although it is limited to the AM2+ versions, the fundamentals remain the same as with the new Phenom II AM3 processors.

For our overclocking tests today, we’ll be sticking with our Phenom II X2 550 dual-core processor. Based upon the same silicone as the popular top-end X4 955, we’re expecting that it should have quite a bit of overclocking headroom in it.

Let’s see how it does in the GD70.


Maximum CPU Core Overclock


Our X2 550 sample has proven to be a very decent overclocker. We had no difficulty achieving a maximum core clock speed of about 3.96GHz. We were oh-so close to reaching that magical 4GHz mark, but we’re afraid that we couldn’t quite keep the processor 100% stable despite our best efforts. We’re confident that with better cooling – like mid-high end watercooling – 4GHz wouldn’t be an issue. Although this is the first board we’ve tried this processor in, we have no reason to believe that it is the motherboard and not the processor holding us back. None the less, a 28% overclock is certainly not too shabby.


Maximum Bus Speed Overclock


The MSI 790FX-GD70 did not disappoint when it comes to Bus overclocking. Ability to hit a reference clock speed of 350MHz in our testing means that the GD70 is an excellent board for pushing standard – i.e. not Black Edition – Phenom II processors to their limits. We should note that the board has difficulty posting at about the 310MHz mark, but once in the operating system, the reference clock could be increased quite a bit more using the OC dial or a software application such as AMD Overdrive. At one point we were pushing beyond 365MHz, but couldn’t quite get the system 100% stable. Amazingly, with a reference clock this high, our memory was pushing 700MHz using the 400MHz divider!
To achieve this high frequency, we ran about 1.4V into the 790FX chipset.


Maximum Memory Overclock


You may be wondering why we’re showing you a screenshot of a super tight 6-6-5 memory configuration running at 716/1432MHz. Isn’t this test supposed to be about maximum clock speeds and not about tight timings? You bet. The problem is that this is the maximum frequency. If we loosened the timings to 9-9-9, we couldn’t do any better than about 735MHz. Increasing CPU-NB voltage to as much as 1.43V didn’t help and neither did any combination of other system voltages. Reducing the NB frequency and HTT frequency also didn’t seem to help. Talk about a serious memory frequency wall. Given that the memory runs at the maximum frequency with super tight 6-6-5 timings only leads us to the conclusion that our X2 550 possesses an especially weak integrated memory controller. This type of hard wall isn’t very uncommon unfortunately. We saw a similar issue – albeit at a higher frequency of 830MHz – during our ASUS M4A78T-E review with an X3 processor. This is an unfortunate reality of AMD’s relatively new entry into the DDR3 market. We’re hoping that as the platform matures, higher memory clock speeds will become a reality.

Although the motherboard does need to provide stable power to the DRAM modules and CPU while maintaining appropriate timing/frequency parameters in the BIOS, the CPU is ultimately what makes or breaks a good memory overclock. Thankfully, tight timings and lower frequencies appear to play nice with most Phenom II processors. Keeping memory at 1333MHz and shooting for CAS6 timings is a good way to keep performance high without stressing the system with higher memory frequencies.