4800+ Brisbane Overclocking - Brisbane Overclocking and Conclusion

Article Index
4800+ Brisbane Overclocking
Brisbane 65nm and Test System
Brisbane Overclocking and Conclusion

Overclocking:

BIOS O/C When it comes to overclocking a new CPU, you have to take things a bit slowly as you find out the limitations of the processor - hopefully without hard-locking your system and having to resort to clearing the CMOS.  Through the week or so we played with this processor we used the CMOS reset option a few times as we ended up pushing things right to the bleeding edge of stable.  The motherboard required the most tweaking as I've never spent too much time with the nForce 590 SLI chipset before.  Thankfully the board has plenty of room to run and we were able to get a high HTT/FSB speed of 380MHz - which is not too bad in my opinion.  In the end, we settled for a couple of CPU overclocks that were completely stable throughout testing.  One setting we used had a high HTT speed using a reduced multiplier and the other used a high CPU speed at the stock multiplier.

For this testing we tried to keep the CPU, RAM and motherboard components as cool as possible through the use of the CoolIT Eliminator and the CoolIT RAM fan.  This combination is not quiet when the fan speeds are turned up, but it does provide very good cooling for the system.  You will be able to see in the screenshots below, that we were able to keep things quite cool when running over 3GHz with this processor.


We started off with stock voltages on the motherboard and the CPU and started increasing the HTT speed after we lowered the CPU multiplier.  At 240Mhz we ran into instability and we upped the voltage on all of the boards chipsets, and lowered the HTT multiplier to 4x.  After this, we were able to reach 315Mhz before we needed to add a little more voltage to the chipsets and up the CPU voltage to 1.35v.  At the 360Mhz HTT mark, we once again ran into issues and had to increase the North Bridge to 1.5v, South Bridge to 1.8v, NB to SB interconnect to 1.57v, and the NB to PCIe voltage to 1.48v.  We also upped the CPU voltage to 1.35v + 0.05v and lowered the HTT multiplier to 3x at this point.  We increased the HTT speed up to 380MHz and that is where we ran into a brick wall.  No matter how much more voltage we pushed through the CPU, chipsets or memory, we couldn't go 5Mhz higher.  Normally when you reach a high HTT speed, you are not stable, but we ran prime95 and Folding @ Home on this machine for hours without issues.  Our high HTT and CPU speed was 380 * 8 = 3040Mhz - which is pretty decent.  On a related note, we also tried lower CPU multipliers, but were not able to attain any higher HTT speed.  The CPU topped out at 3.04Ghz in this scenario.

High FSB Speed

 

Using similar voltages as maximum values, we also tried to see how high we could get the CPU when using the stock multiplier of 12.5.  We managed to squeeze a bit more out of this CPU as we topped off at  250Mhz * 12.5 = 3125Mhz.  The system would post at 255 HTT, but would not load Windows.  When we loaded Windows at 3.215GHz - we were able to run completely stable during hours of stress testing.

 High CPU Speed

 

Conclusion:

We didn't publish any benchmarks of the processor overclock because they are almost identical to the 6000+ X2 processor that we reviewed last month.  At 3.0GHz (6000+ Stock, 4800+ O/C) we see performance numbers that are so close, it is too boring to publish.  Performance between them is with 1%-2% and that lies within margin of error.  We were really hoping to reach a high Overclocked speed of 3.3GHz, but fell a little short.  As I look around the web at other 65nm Brisbane reviews, I find that our CPU fell right in the middle of the pack in terms of overclockability.  

When comparing the 4800+ X2 Brisbane's overclocking ability to Howdy's 4800+ X2 Windsor, I was able to overclock the Brisbane a little more.  However, the smaller L2 cache on the Brisbane could actually hamper performance a bit on very intensive applications.  Regardless, I was able to clock up about 300MHz more on the Brisbane than we could on the Windsor.

 

Pros:

  • Good Price/Performance
  • Overclocks well
  • Stock speed power consumption a mere 65W
  • Good choice for enthusiasts that want 6000+ performance with a smaller price tag.

Cons:

  • Reported slower cache latency
  • 65nm process doesn't add anything exciting

BCCHardware.com Rating
Quality:
9/10
Performance:
8/10
Overclocking:
8/10
Stability:
8/10
Features:
7/10
Value:
8/10
Total Score 8.0

I'd like to thank MemoryExpress for sending over this processor and motherboard for us to play with.  We are hoping to get more Brisbane CPU's in the near future to compare in more detail.  If you have any questions or comments about this article, please head on over and post them in the forum at the comments link below.