We pointed out the other day that AMD will have two or (somewhat later) even three types of processors available for each speed bin: Palominos, TBredAs and TBredBs.

To make your life easier, this will tell you how to tell them apart.

The Approach

There's two ways to buy a CPU, either over a website, or in person.

Websites rarely list CPUs by stepping code. They will, however, often list CPUs on their webpages and provide their OPNs. That's the ordering number.

So long as we have all these different type processors around, you should NOT order from any place that doesn't have the OPN listed along side the processor. If you do, you could well end up with a Palomino when you expected to get a TBred, or get a TBredA when you expected a TBredB. After all, the webpage said you were going to get an XP1800 or whatever, not that it was a Thoroughbred. If you want to send it back, expect to get hit with a restocking fee if the place has one.

On the other hand, if you order from a reseller that shows the OPN on the webpage (and save the webpage) and the OPN on the webpage indicates a Thoroughbred, if you get a Palomino, you're protected. They didn't send you what you ordered, and you have proof of it.

If you think I'm overly paranoid, well, I've been in this situation, and it works.

Never accept a salesman's verbal word that you'll get the "right" one. Most places have their goods in warehouses, often miles and miles away. The salesperson couldn't find out even if he wanted to, and many salesmen will tell you anything to get the sale, then deny it later. Always get it in writing before you order, any reputable place will be happy to do that if it's possible.

Website pages aren't always accurate. If there is any contradiction in the description of the item (i.e., the product is called .13 micron or "latest technology," but it has a Palomino OPN, either find another place, or email the reseller asking for written confirmation on just what it is they are selling.

What I've said works fine with OEM chips; retail boxes are another story, especially if you're buying in person. I just haven't looked at these boxes lately. Could somebody who can look at some tell me what kind of identifiers are on the outside of the box that might let people identify what they're getting?

Which Codes Mean What

To make this easy, what you need to know is listed by processor speed.

The OPN information is printed somewhere on every AMD CPU. For all Palominos, if you're looking at one, the OPN is the first code printed on the core of the CPU located in the middle of the processor. For all Thoroughbreds, the OPN the first code printed on the black area on one edge of the CPU.

This information is based on current AMD datasheets, which are subject to change. We'll update as needed.

There are three critical indicators in the OPN.

AX1700DMT3C: Voltage
AX1700DMT3C: Maximum temperature
AX1700DMT3C: FSB Speed

The following codes mean the following:

Voltage

L: 1.50V
U: 1.60V
K: 1.65V
M: 1.75V

All Palominos have default voltage of 1.75V, so all Palominos have voltage code of "M." TBredAs have a default range of 1.5-1.65V. TBredBs have a default range of 1.6V-1.65V.

Maximum Temperature

T: 90C
V: 85C

All AMD processors with a rating less than 2200+ have a maximum temperature of 90C, so they're all "Ts." Anything above that has a max temp of 85C, so they're all "Vs." FSB Speed

C: 266MHz
D: 333MHz

Here's how these codes translate in real life with real chips:

Two Kinds of TBredBs

There are high-end and low-end TBredBs. They aren't all the same. The high-end ones on average perform several hundred MHz better than the low-end ones. Update 3/28/03: The gap between the two has narrowed somewhat with the latest (week 8 and thereafter) "J" chips.

You can identify which type of TBredB it is by looking at code that begins the second line of coding on the processor. If you see a code like "AIUHB" that begins with the letter "A," that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J," that's a low-end TBredB.

Here's how these codes translate in real life with real chips:

1600+

Palominos: If the website you're ordering from shows an order code of AX1600DMT3C, that's a Palomino.

TBredB: If the website you're ordering from shows an order code of AXDA1600DUT3C, that's a Thoroughbred B.

1700+

Palominos: If the website you're ordering from shows an order code of AX1700DMT3C, that's a Palomino.

TBredA: If the website you're ordering from shows an order code of AXDA1700DLT3C, that's a Thoroughbred A. Update 3/28/03: It appears that from week 8 of 2003 and afterwards, there are 1.5V TBredBs with the same code.

All TBredAs have a stepping code which ends in "A," like "AIUGA." All TBredBs have a stepping code which ends in "B," like "AIUGB."

TBredB: If the website you're ordering from shows an order code of AXDA1700DUT3C, that's a Thoroughbred B.

If you see a code like "AIUHB" that begins with the letter "A" on the second line of the processor codes, that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J" on the second line of the processor codes, that's a low-end TBredB.

As of now (1/15/03), all TBredBs sold at this speed are low-end "J" TBredBs.

1800+

Palominos: If the website you're ordering from shows an order code of AX1800DMT3C, that's a Palomino.

TBredA: If the website you're ordering from shows an order code of AXDA1800DLT3C, that's a Thoroughbred A. Update 3/28/03: It appears that from week 8 of 2003 and afterwards, there are 1.5V TBredBs with the same code.

All TBredAs have a stepping code which ends in "A," like "AIUGA." All TBredBs have a stepping code which ends in "B," like "AIUGB."

TBredB: If the website you're ordering from shows an order code of AXDA1800DUT3C, that's a Thoroughbred B.

If you see a code like "AIUHB" that begins with the letter "A" on the second line of the processor codes, that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J" on the second line of the processor codes, that's a low-end TBredB.

As of now (1/15/03), all TBredBs sold at this speed are low-end "J" TBredBs.

1900+

Palominos: If the website you're ordering from shows an order code of AX1900DMT3C, that's a Palomino.

TBredA: If the website you're ordering from shows an order code of AXDA1900DLT3C, that's a Thoroughbred A.

TBredB: If the website you're ordering from shows an order code of AXDA1900DUT3C, that would be a Thoroughbred B.

If you see a code like "AIUHB" that begins with the letter "A" on the second line of the processor codes, that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J" on the second line of the processor codes, that's a low-end TBredB.

However, AMD's datasheets do not currently show a 1900+ TBredB, and as of now (1/15/03), there have been no sightings of any. Since both the 1800+ and 2000+ TBredBs have a default voltage of 1.60V ("U"); it's very safe to say any 1900+ TBredB will also.

2000+

Palominos: If the website you're ordering from shows an order code of AX2000DMT3C, that's a Palomino.

TBredA: If the website you're ordering from shows an order code of AXDA2000DKT3C, that's a Thoroughbred A.

TBredA/B: If the website you're ordering from shows an order code of AXDA2000DUT3C, that could be either a Thoroughbred A or Thoroughbred B. The only way to distinguish between the two is by the stepping code.

All TBredAs have a stepping code which ends in "A," like "AIUGA." All TBredBs have a stepping code which ends in "B," like "AIUGB."

There's two listed TBredA types in the AMD techdoc. One uses 1.6V, the other uses 1.65V. The TBredB is solely 1.6V.

If you've determined a CPU is a TBredB, if you see a code like "AIUHB" that begins with the letter "A" on the second line of the processor codes, that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J" on the second line of the processor codes, that's a low-end TBredB.

As of now (1/15/03), there have no sighting of TBredBs, and only one sighting of a TBredA at this speed.

2100+

Palominos: If the website you're ordering from shows an order code of AX2100DMT3C, that's a Palomino.

TBredA/B: If the website you're ordering from shows an order code of AXDA2000DUT3C, that could be either a Thoroughbred A or Thoroughbred B.

All TBredAs have a stepping code which ends in "A," like "AIUGA." All TBredBs have a stepping code which ends in "B," like "AIUGB."

If you see a code like "AIUHB" that begins with the letter "A" on the second line of the processor codes, that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J" on the second line of the processor codes, that's a low-end TBredB.

As of now (3/28/03), the only sighting of 2100+ TBreds have been TBredsBs, and they have all been high-end TBredBs.

2200+

TBredA: If the website you're ordering from shows an order code of AXDA2200DKV3C, that's a Thoroughbred A.

TBredB: If the website you're ordering from shows an order code of AXDA2200DUV3C, that's a Thoroughbred B.

If you see a code like "AIUHB" that begins with the letter "A" on the second line of the processor codes, that's a high-end TBredB.

If you see a code like "JIUCB" that begins with the letter "J" on the second line of the processor codes, that's a low-end TBredB.

As of now (1/15/03), no TBredBs have been sighted at this speed.

2400+

Sorry, no exciting choices here (yet). They're all TBredBs, and they'll have an order code of AXDA2400DKV3C.

Yes, the DKV part is the same as for the 2200+. That's because a TBredA runs at 1.65V (that's what the "K" stands for) at 2200+. A TBredB runs at 1.6V (that's what the "U" stands for) at 2200+ and 1.65V at 2400+ and above.

As of now (1/15/03), all sightings of the 2400+ and faster CPUs have been high-end TBredBs.

2600+

These are all TBredBs, too, but just in case "which one I am getting" is getting old, the 2600+ gives you a new, different challenge: What Speed Am I Getting? There will be two 2600+s, but they'll run at different speeds. Since the 333MHz bus helps performance, AMD figured (correctly) that a CPU running at a slightly lower speed and higher bus was the same as a CPU running at a higher speed and a lower bus.

The 2600+, 266MHz version, will run at 2133MHz.

The 2600+, 333MHz version, will run at 2083MHz.

We'll no doubt see more situations like this as the number of 333MHz processors expands.

The way you tell these apart by OPN is that the 266MHz processors will always have an OPN that ends in "C," while the 333MHz processors will always have an OPN that ends in "D."

Next spring, we'll get more of the same when Bartons show up. You'll have Bartons and TBreds running at the same speed, too.

Good luck.

Ed