Unlocking & Overclocking The AMD Slot A Thunderbird

Unlocking & Overclocking The AMD Slot A Thunderbird - Page 2

Unlocking & Overclocking The AMD Slot A Thunderbird
Straddling the fence between the old and the new

July 4, 2000 - By Dave Altavilla

HotHardware's T-Bird Test System
A little un-orthodox

Full Tower ATX Case w/ 300W PS,  Slot A Thunderbird Athlon 700 (provided by Azzo Computer), Gigabyte GA-7VX (full review soon), 128MB of PC133 SDRAM, WD Expert AC418000 7200 RPM ATA66 Hard Drive, Elsa Gladiac, Kenwood 72X CDROM, Win 98SE,
NVidia 5.30 Drivers, DirectX 7.0a

Installation / Setup On A KX133 Board
Not "fully supported" but...

Alright then, let's get something out in the open here.  The Slot A Thunderbird Athlon from AMD is a chip that quite frankly isn't supposed to be in the reseller channel.  However, the crafty folks at Azzo Computer, as well as a few other on line retailers, have gotten a hold a these chips and are making them available for sale as long as supplies last.  AMD is really only manufacturing the Slot A version of the chips for certain OEMs that have Slot A motherboard designs still in the production flow.  The Socket A version is intended for the R.O.W. (rest of the world) demand and there are currently several motherboards released based on the VIA KT133 chipset which support this socketed version.  Now, having said this, the only currently shipping Slot A chipset that "officially" supports the Slot A T-Bird, is the AMD 750.  The current version of the Slot A chipset from VIA, the KX133, only "officially" supports the older version of the Athlon with discrete cache on the PCB. 

With this in mind, you are probably thinking, "why take one step forward to go one step back"?  For the users out there who are currently running a motherboard based on the AMD 750 chipset, the Slot A Thunderbird will provide new levels of performance with just a drop in solution.  For those users who are looking at an entire new platform however, you would be hard pressed to opt for the AMD 750 based boards on the market when the VIA chipset based solutions provide the PC133 Memory and AGP 4X support that the 750 doesn't have.  So, where does this leave the Slot A?  Well, frankly somewhere in between the old PC100 and the new PC133 platform for the Athlon.

HOWEVER, we decided to see what would happen when we tried to setup the Slot A T-Bird on a KX133 board.  We were pleasantly surprised to see that indeed it did run and was stable.  In our tests, we used a new Gigabyte KX133 board, the GA-7VX.  It supports all of the usual features of the KX133, including ATA66, AGP4X, PC133 Memory and PC Health Monitoring. 

We'll have a full review of this board shortly but for now here is the obligatory "candid photo"....

(click for larger image)

Again, more on this board when our boy "BigWop", delves into it with a full review.  However, suffice it to say that Gigabyte has some of the most stable motherboards on the planet in our opinion.  They may not always have the widest assortment of features but the quality is definitely in there.  Again this board was stable with our 700MHz. Slot A T-bird at stock speed and with a little bit of over-clocking.  We want to be very specific here however, again this chipset does not "officially" support the T-Bird, at least for now.  Your experience with a KX133 board and a Slot A T-Bird depends on many factors including among other things, a robust and clean power source.  We used a Power Man 300 Watt unit and it did the job nicely.

In addition, we have heard from one very popular and large Motherboard Manufacturer that they are working on a BIOS revision for their current KX133 Slot A board, which should bring full stability to the mix.  As soon as we get details on this, we'll let you know.  This could be VERY good those of us looking to "unlock" the T-Bird since the easiest way is with a GFD (Gold Finger Device) on a Slot A version CPU.

So, with that lead in, let's take a look at the over-clocking side of things shall we?

Overclocking The Slot A Thunderbird
Just like any other Athlon

We have good news for those of you who are not shy to crack open the case of an Athlon, exposing the "Gold Fingers" on top of the PCB.  The Outside Loop Afterburner DOES work with the new Slot A T-Birds.  It works exactly as the standard Athlon does and we were able to change the multiplier with it. 


On the top left of the PCB, you can see the Gold Fingers.  We also used a rather large Global Win Heat Sink and Fan combo with decent thermal paste joining the two.  On the right is the full setup with the Afterburner installed. We used the GA-7VX Motherboard's ability to change the Front Side Bus speed and dialed in stable at 115MHz. FSB.  The Afterburner allowed us to run at a multiplier of 7.5, only a half step higher than the stock multiplier.  However, this was the highest speed at which the processor would run stable with our standard mainstream cooling solution.  The voltage was dialed in to 1.85V which seemed the best level for stability.   

Now, in summary, I think we were fairly successful here with our Slot A T-Bird, in the over-clocking department.  From what we have seen of early Socket A T-Bird reviews, with the current multiplier lock (operative word is "current" here), they are only able to over-clock to about 10% over their stock speed since front side bus speeds over 115MHz. tend to bring out the "flakies" on the Athlon's EV6 bus type.  Our processor's native clock speed of 700MHz. was exceeded by almost 20% to a high of 863MHz.

For now, the only "unlocked" T-Birds will be the Slot A version.  We have heard of one motherboard manufacturer that is claiming to have unlocked the Socket A chips with specific pins that AMD designates for the multiplier.  We are making an effort to get a hold of one of these boards, when they are available and will keep you posted.

So, now that we have covered the basics here.  Let's dig in deeper on the performance side of things!


Benchmarks With The Unlocked T-Bird



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