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Green vs. Blue Cores


Date
: 12/6/00 – 10:24:47 PM

Author
:

Category
: Misc

Manufactor: AMD

Introduction

Since AMD has been manufacturing their Tbird and Duron cpu’s, speculations about blue cpu cores vs. green cpu cores have been spreading all around the net. Most people are claiming that the blueish cores are actually overclocking better then the ‘greenies’. OC Online wanted to find out the truth about this and started investigating, specifically Duron CPUs. Please join us in our adventure though the world of the ‘greenies’ and the ‘blueies’ and get to the bottom
of this!

What is it all about?

The green or blue color you see when you look at the cpu core is actually a very thin layer of polish to protect the core as much as possible. The core remains very fragile, and like I already proved to you, it is very easy to destroy it!

Some people say that the blue core means that AMD used copper interconnects in the cpu. This is NOT true since AMD is not manufacturing any ‘copper’ Durons. They are all manufactured with aluminium interconnects. The Duron cpu’s are all made in AMD’s FAB25, which is located in Texas.

Like I said, all Durons are made with aluminium interconnects. The Athlon ‘TBird’ cpu’s are made with both aluminium and copper interconnects, especially the higher clocked Athlons.

All the cpu’s that are manufactured in Texas have a green colored core and all cpu’s made in AMD’s other fab, located in Dresden, have blue (or purple) colored cores. Also, cpu’s with copper interconnects are made only in Dresden, which is why most people think that cpu’s with a blue core feature these copper interconnects.

But how does one explain that there are also blue/purple colored Durons on the market? You would think that this is impossible, since all Durons are made in Texas, and the fab in Texas only uses green polish.

But why is it that important that a cpu has copper interconnects instead of the ordinary alumium ones? Why is it that cpu’s with copper interconnects are expected to overclock better then the same cpu’s with aluminium interconnects?

There is a very logical explanation for this actually. Copper offers a much lower electronic resistance then aluminium, and it has way better
electro-migration properties. This means that the signal that goes through the cpu is much ‘clearer’ and ‘more pure’ than the same signal would be in a cpu with aluminium interconnects, which would suffer more from signal distortion and resistance. In a 1GHz cpu the signal moves so fast that the smallest distortion could cause a crash of the cpu. Since copper can guide this signal much better then aluminium, all the fast cpu’s like the +1GHz AMD TBird’s are build with copper interconnects.

This is also the reason why a ‘copper’ cpu should overclock better then a normal ‘aluminium’ one. Of course this is all pure theoretical stuff, but I believe there is much truth in it.

Now, what would you do if I were to tell you I have pictures of a blue/purple Duron cpu? That’s right…OC Online has a blue colored Duron in one of our computers.

Some Pictures…

Ok guys (and gals of course), here are the pics. I put a ‘blue’ Duron 600 next to a ‘green’ Duron 800 so you can see the difference in color very clearly.

Like the pictures show you, the blue/purple Durons do exist and are available on the market. I can not tell you how it is possible as there is no logical explanation for it. Did the Texas fab run out of green polish, and use the blue polish for a day or two? Were there some Durons made with copper interconnects? Who can tell?

Overclocking

What we really are interested in, is the ability of these cpu’s to overclock. Does the ‘blue’ Duron overclock better than the ‘green’ Duron? This is what we all would like to know of course. I shall no longer keep you guys in such suspense.

To be able compare both cores to each other, we need two Duron cpu’s: one with a blue core and one with a green core. The blue cored cpu is a Duron 600 which we got from The Overclockerz Store. The green colored Duron is a Duron 800 whch was supplied to us by MPL.

Both cpu’s were installed in the best overclocking board available: the ABIT KT7 RAID. To cool these mofo’s down, we used a GlobalWin FOP38 cooler. This beast is the best socketA cooler available featuring a 7000rpm 60mm ball bearing fan which will cut your arm off if you’re not careful!

To determine if the cpu was stable, I ran Prime95 for 4 hours on each cpu and after that I let Q3: Arena demo001.dm3 run for halfan hour. If an overclocked cpu can survive this, you can bet your mom’s cat on it that the cpu is stable.

The ‘blue’ Duron 600 was able to cruise at an amazing 1040MHz using 1.85v core voltage. I was able to boot Windows 2000 at 1050MHz but it was not stable anymore at that speed. Still a nice achievement for a 600MHz cpu I think.

Next cpu to throw into the arena: the Duron 800. Again we tried overclocking this ‘green’ monster, and after some time the cpu settled at an amazing 1080MHz, also with 1.85v core voltage. Yep, that’s 40MHz faster then the ‘blue’ Duron.

The cpu’s were both unlocked using the pencil method, and were run at the lowest possible fsb because we did not want the memory, or any other factor being the bottleneck of this test. A copper shim supplied by CPU F/X was used, so the heatsink was aligned perfectly with the cpu. We also reapplied thermal grease for every cpu.

Some of you will say that the Duron 800 overclocked better because it has better quality silicon. In my opinion this is just plain bull as there is no difference between a Duron 600, Duron 700 or even a Duron 800. The only difference is the multiplier lock and the text on the cpu itself. There can only be a difference of quality if AMD uses another stepping for the 800MHz cpu
compared to the 600MHz one, but this is not the case with my cpu’s.
Of course there will exist better and worse cpu’s since the ones made from the center of the silicon wafer will have better quality stuff then the ones made from the outer piece of the wafer.

In my tests, both cpu’s ran at the same temperature while running at the same speed. At 1000MHz this meant they were somewhere in between 40 and 45 degrees
celcius. This is a normal temperature for AMD cpu’s and since AMD tells us that their cpu’s can handle everything up to 60 degrees celcius, I was not worried with these temps (although I think you should worry when your cpu runs at 60 degrees celcius!).

Conclusion

So what does all of this tell us? Well it seems that the myth about the ‘blue’ Durons being better then the ‘green’ ones has come to an end here and now. The Duron 800 beat the ‘blue’ 600MHz version by a nice margin, which proves that the color of the core has nothing to do with it at all.

So next time you go out and buy a Duron, there is no need to look for a blue one instead of a green one because it won’t make any difference at all.