Unlocking & Overclocking The AMD Slot A Thunderbird

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

July 4, 2000 - By Dave Altavilla 

In this weeks installment of "my PC is faster than yours", we have a new processor that has emerged in the High End space.  AMD's long awaited Thunderbird (god I love that code name) has arrived and it's sporting 256K of on chip full speed L2 Cache.  Along with this new CPU, we will be using a new motherboard from Gigabyte, the GA-7VX (full review coming soon), designed around VIA's new KX133 chipset affording AGP4X and PC133 memory support to the Athlon platform.  The combination of this new round of technology from the two primary Intel competitors, has painted a landscape of options for the end user. 

This is a HotHardware evaluation and a project of sorts, with two very mainstream products in the AMD platform.  We are pairing the Gigabyte GA-7VX with the AMD Thunderbird Athlon 700MHz. Processor.  Both of these products are very reasonably priced and should be as much of an "average" users configuration as any mid range Intel base platform on the market.  We'll look at the features and performance.  Then, just for the "fun factor", we'll over-clock the stuffing out of it (no Vapochill here, just standard equipment) to see what it will do.  In addition, there are some subtle nuances you need to be careful of with any new architecture.  More on this later.

We would like to start this review off right by giving thanks to our good buds over at Azzo Computers for hooking us up with the T-Bird 700.  We don't make to many recommendations around here, on where the best places are to buy your hardware but when we do, they have to be top notch people to get our plug.  Azzo is definitely one of those places.   

Now, let's look at our setup.
 

Specifications Of The Bird Cold Hard Cache

Historically, the Athlon core was populated on a multi chip printed circuit board for the Slot A configuration.  The SRAM L2 Cache was installed on the CPU Module discretely.  This allowed for a large cache size but slower access times and getting on and off the CPU core to access that cache was slower than the integrated solution of today.

Look Ma!  No SRAM chips! (click image)

This is an image of the new Athlon that AMD code named "Thunderbird".  As you can see in this shot, there are no SRAM chips on the PCB.  All of the T-Bird's SRAM cache is now on chip and running at full speed with the processor.  You may have already seen the Socket A version of the T-Bird which is set up for a 462 Pin Grid Socket.  In the event you haven't yet, here is what this chips looks like.

Just keep in mind that we will be taking a look at the SLOT A version of this chip, as shown in the top shot.  This will be important to remember later on in our tests.  Here are the rest of the specifics for the T-Bird.  Both chips have the same electrical specs with the exception of the form, factor obviously.

• Multiple parallel x86 instruction decoders

• Three out-of-order, superscalar, fully pipelined floating point execution units, which execute x87 (floating point), MMX? and 3DNow!? instructions

• Three out-of-order, superscalar, pipelined integer units

• Three out-of-order, superscalar, pipelined address calculation units

• 72-entry instruction control unit

• Advanced dynamic branch prediction

• Enhanced 3DNow!? technology for leading-edge 3D performance

• 21 original 3DNow! instructions-the first technology enabling superscalar SIMD

• 19 new instructions to enable improved integer math calculations for speech or video encoding and improved data movement for Internet plug-ins and other streaming applications

• 5 new DSP instructions to improve soft modem, soft ADSL, Dolby Digital surround sound, and MP3 applications

• Compatible with Windows® 98, Windows 95, and Windows NT® 4.x without software patches

• 200MHz AMD Athlon? system bus enabling leading-edge system bandwidth for data movement-intensive applications

• Source synchronous clocking (clock forwarding) technology

• Support for 8-bit ECC for data bus integrity

• Peak bandwidth of 1.6 to 3.2 GB/s

• Multiprocessing support: point-to-point topology, with number of processors in SMP systems determined by chipset implementation

• Support for 24 outstanding transactions per processor

• 128K of L1 cache and 256K of integrated, on-chip L2 cache for a total of 384K full speed, on-chip cache

• Slot A - Available in processor cartridge with mechanical dimensions comparable to Pentium® III.  Leverages existing physical/mechanical Slot 1 PC infrastructure, including mechanical connector, but with different bus protocols and electrical definitions

• Electrical interface compatible with 200MHz AMD Athlon system bus, based on Alpha EV6 bus protocol

• Socket A - Available in Pin Grid Array (PGA) for mounting in a socketed infrastructure
  Electrical interface compatible with 200MHz AMD Athlon system bus, based on Alpha EV6? bus protocol

• Die size: approximately 37 million transistors on 120 mm² die on 0.18-micron process technology

If you look at this architecture from a "specsmanship" standpoint, one would have to admit that AMD has Intel beaten for the most advanced architecture in PC processors right now, at least for what is available on the market today.  Again, the two main strong points here are that the internal system bus runs at 200MHz. and the on chip cache is running at full speed with the processor.  The later of the two bullets is something that Intel has had since the earlier days of the P3 and it is why AMD lagged slightly in performance on some applications, until now.  Finally, there is also support for Multi-Processor systems although there are no motherboards or chipsets shipping currently that support it.

So, in an effort not to bore you with an over-abundance of technical detail, let's plug our new "Winged Bird" in and hit the power button.

Installation, Setup, stability  and Overclocking