It's been out for awhile, so by now all of you should know about the last Thunderbird - C to be released. The Thunderbird 1.4GHz ends a long line of Athlon Thunderbird cores we all know and love, introduced over a year ago. AMD is revising it's Athlon line to include include the newer Athlon 4 and Athlon MP, and the controversial Athlon XP. These new CPUs will contain newer instruction sets, multiprocessor capability, and run cooler. The Athlon XP introduces (or reintroducing depending on who you ask) the performance rating system. With Intel holding the market mindset with their higher clocked CPUs, AMD is introducing this PR system to close the gap. An Athlon XP may be a 1.4GHz part, but it will have a PR rating of 1.6+GHz, since it performs in between the 1.5 and 1.7GHz Pentium 4 or classic Athlon. I have my opinions about this (I hate it), but that's not the focus of today's review.

The Thunderbird we're going to look at here is the 266MHz version, which performs quite a bit better than the older and more rare 200MHz part. You'll need a motherboard that supports the 133FSB (effectively double pumped to 266MHz) to take full advantage of it's features. Other than the different clock speed, the 266MHz part is identical to the 200MHz part.

Specifications

Here are some of the technology features, straight from AMD:

The industry's first nine-issue superpipelined, superscalar x86 processor microarchitecture designed for high clock frequencies:

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 additional 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 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

266MHz or 200MHz AMD Athlon" processor system bus enables 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 data rate of 1.6 to 2.1GB/s (depending on processor bus speed)
Multiprocessing support: point-to-point topology, with number of processors in SMP systems determined by chipset implementation
Support for 24 outstanding transactions per processor

Pictured is the OEM version of the CPU. You're likely aware that CPUs, and other parts, come in either OEM or Retail packaging. Generally, the major difference is that Retail items carry a more comprehensive warranty, contains drivers, instructions, manuals, and a fancy box. OEM CPUs, for example, come in a Styrofoam wrap, and no heatsink, unlike a Retail CPU which does. No big deal, since a hardcore enthusiast will likely get a real heatsink. Performance and overclocking potential are relatively comparable. In other words, at stock speed, they perform within spec, but as always in overclocking, your results will vary.

Basically, all you really need to know is that it's fast. I'm not going to expand much more than what AMD says in terms of features. You've seen one Thunderbird, you've seen them all. Other than scoring closely with Intel's greatest, clock for clock (and sometimes beyond), the Thunderbird's claim to fame is it's overclocking ability. Jealous of your Mom's 1.5Ghz eMachine? Crank your Thunderbird to 1.55Ghz and taunt your Mom. Actually, that was just a hypothetical example. A 1.5Ghz eMachine doesn't exist, and you should be nice to your Mom.

Overclocking

Why overclock? The answer is simple, free performance. I know it can be argued that a faster CPU isn't much more expensive, so why not avoid buying porn, erm, I mean Math textbooks for a week, and buy a faster proc? I don't really have an answer for that. I can afford my faster CPUs and my porn, I mean books, but for many, overclocking is a hobby. And believe me, the 1.4Ghz Thunderbird overclocks well.

What is the recipe for overclocking an Athlon? Well, other than luck, it'd be good to know what core you're buying. This will be the first 4 - 5 letters on the third line of the core, 2 lines if you don't count the bold AMD Athlon. The first core revision that drove people bananas was the AXIA core Athlons. These puppies were sold at various speeds, but the 1Ghz part was a very overclockable part, reaching anywhere from 1.33 to 1.4Ghz and up! Other cores followed, but not quite meeting the expectations set by the AXIA CPUs. The AYHJA core, as pictured above, is the next most "overclockable" part, and is sought after greatly by those dreaming of 1.6Ghz+. Does it meet those expectations? I'll tell you later.

Though tricky at first, overclocking is easy to do once you've armed yourself with some knowledge. You'll find sources everywhere, but it all boils down to this..., you can overclock via the multiplier, or the FSB, or both. My stock speed is 10.5x133 = ~1400, where the equation is 10.5(multiplier) x 133(front side bus). By manipulating either number, you can give your CPU a small, or large boost. Just be warned that everyone's results may vary, and overclocking raises the chances of you torching your CPU. Remember to get a good heatsink, like those reviewed here in August, to aid in cooling. I also suggest reading and check their site out in depth. They have an answer to every question you may have, and they're an invaluable source of info.

Though overclocking with the multiplier or FSB will work well, with AMD, most choose to overclock with the multiplier. Anyone who has overclocked the Pentium III can attest that an increased FSB will also mean increased stress on your AGP/PCI parts. Though modern day peripherals can take it to an extent, there is no guarantee on the stability. By overclocking via the multiplier, only the CPU is stressed, so with the proper cooling and voltage adjustments, you'll be on your way to high speed nirvana.

All Thunderbirds 1.2Ghz and up are factory unlocked. That means that the multiplier is free for your manipulation. I highlighted the magical L1 traces. This is where you may have heard the ole "pencil" trick of connecting these typically separated traces. I'm not sure why, but pretty much all the new 266FSB Thunderbirds do not have these traces cut. The 200FSB Athlons almost certainly do.

Test Bed

AMD Thunderbird "AYHJA" Core, 1.4GHz (10.5x133), 1.6 (12x133), 1.61 (12x134), 1.61 (12x140)
ABIT KG7-RAID
512MB Kingston Value DDR ram
2 x 60GB Maxtor Diamondmax, RAID-0
MSI StarForce 822 GeForce 3, Det. XP v21.81

Windows XP
VIA 4 in 1 v4.33

I am not going to bombard you with every possible overclocking combination, but rather post only the results that were successful. What that means is that only the highest overclocking results that was able to allow me to play 30 minutes of Quake 3, run SiSoft Sandra and CPUID, without crashing will be displayed. I managed overclocks at lower speeds (but higher than stock), but there's no point of displaying them. vCore settings were 1.85v for all the overclocked scores.

Sisoft Sandra - CPU

(left) 1.4GHz (1.75v, 10.5x133) and (right) 1.6GHz (1.85v, 12x133)

At 1.6Ghz, the Thunderbird destroys all the recorded systems in SiSoft Sandra. 12x133 ran perfectly, but any higher multiplier was a no go.

Sisoft Sandra - CPU

(left) 1.61GHz (1.85v, 12x134) and (right) 1.61GHz (1.85v, 11.5x140)

Here, we concentrate more on the FSB. I'm not sure why these scored lower than 12x133. Usually, the faster FSB will outperform adjustments by multiplier alone. At a multiplier of 12x, I couldn't even get a FSB of 135, but managed 134FSB instead. For comparison purposes, I wanted a FSB combined with a lower multiplier to see if the FSB would be faster. 140FSB was the most stable I was able to attain, which is too bad since I've seen higher online, and at 140, it only marginably outperforms 134.

CPUID

(left) 1.4GHz (1.75v, 10.5x133) and (right) 1.6GHz (1.85v, 12x133)

(left) 1.61GHz (1.85v, 12x134) and (right) 1.61GHz (1.85v, 11.5x140)

I mentioned earlier that the in-between overclocking attempts worked, but extreme overclocking didn't. I posted the fastest scores that were able to allow me to play Quake 3 for about two 20 minute maps, and run the SiSoft benchmarks. Like I said, vCore was kept at 1.85v, but I didn't mes around with memory timings since I wanted an even playing field. Temps never passed 53C on the Swiftech MC462A.

12x155 - Did not Post
12x145, 12x141 - Post, Reboot at NTLDR
11.5x155, 11.5x141 - Post, Stop Error
11x 150, 10x155 - Post, Windows lock at Log on

As you may know, one of copper's assets is it's ability to absorb heat. I read on , that at initial power on, since there is a tremendous blast of it, the copper-base Swiftech was able to handle it, and allow the CPU to initially post at some crazy speeds. Too bad I couldn't get further.

Final Words

I'm sure you've read everywhere that AMD kicks the Pentium 4 around at every bechmarks. Even here, with SiSoft, a traditionally Intel friendly benchmark tool, clock speeds being equal, the overclocked Thunderbird rules the roost. Since I don't have a P4 in house, I'm not going to hand the trophy to AMD, especially when my Quake 3 benchmark is still a lot lower than published P4 scores.

On the bad side of things, I'm sure you've heard of the cracking of Athlon CPU cores with a badly installed heatsink. This does happen, and I've seen friends lose CPUs. Friends who know what they're doing. Most of the time, it can be attributed to a poor clipping system on the heatsink, but no doubt, there's a reason why CPU shims are so popular. Another problem is the lack of a thermal diode. This is bad because if your Thunderbird isn't getting enough cooling, it doesn't know that. 6 seconds later, you'll smell smoke and your house will burn down. Hopefully, that won't happen, but it's a shame that this is a feature included only with the newer Athlon XPs.

Is the Thunderbird 1.4Ghz something you need? Well, truth is, it's a damn fast CPU. It's stable, overclocks well, and is a pretty good bargain right now. The Athlon XP looks impressive, and from the reviews this week, it looks to be a compelling product. Still, the Thunderbird doesn't get blown away, and unlike the XP, the Tbird is easier to overclock (for now).

At this time, if anyone wants to upgrade, I'll tell them to wait another few days when the XP will be on the shelves. I'm scoring the Thunderbird 1.4Ghz a decent score today, based on performance, but I can't recommend it because the Athlon XP is now here. Then again, that all depends on where you actually live. Certainly, if saving 50$ or so is important, and/or the XP's ETA is unknown in your area, get the Thunderbird 1.4Ghz. It sure won't dissapoint you.

Pros: Good performance, decent overclocking potential.

Cons: No internal thermal diode, runs extremely hot, fragile construction, quite expensive in the price to performance ratio compared with other Athlon.