The Chips

Launching on the socket 939 platform today are the Athlon 64 3500+, 3800+ and FX-53 CPUs. As we have mentioned in previous news articles, these new CPUs include the 3500+, 3800+ and FX-53. The 3500+ will run at 2.2GHz while the 3800+ and FX-53 will run at 2.4GHz each. Here's a comparison shot of a 940 pinout and a 939 pinout:


This is a socket 940 processor


This is a socket 939 processor

Aside from the difference in packaging, the only new thing about these processors is their on die memory controller. These parts are the first to be equipped with a memory controller that can handle dual channel unbuffered DDR memory. As we have seen, integrating a memory controller on die has been a successful way of maintaining performance for AMD, but the drawback is when AMD wants to make its processors work with a new type of memory: they need to redesign part of the silicon.

Here's a table that lays out the processors and their specifications adopted from one of our earlier roadmap articles:

Current AMD Athlon 64 and FX processors
  Clock Speed Cache Size Dual Channel Unbuffered
Athlon 64 FX-55 (939)
2.6GHz
1MB
Yes
Yes
Athlon 64 FX-53 (939)
2.4GHz
1MB
Yes
Yes
Athlon 64 FX-53 (940)
2.4GHz
1MB
Yes
No
Athlon 64 3800+ (939)
2.4GHz
512KB
Yes
Yes
3700+ (754) ???
2.4GHz
1MB
No
Yes
Athlon 64 3500+ (939)
2.2GHz
512KB
Yes
Yes
Athlon 64 3400+ (754)
2.2GHz
1MB
No
Yes

The questions are next to the 754 pin 3700+ part because we haven't seen one yet, and we didn't run any numbers for that particular configuration.

The 939 pin Athlon 64 parts we know about have 512kB L2 caches, this means that he 3500+ actually has less cache than the equivalently clocked 3400+ 754 pin CPU (the same is true when comparing the 3700+ 1MB part to the 3800+). If we are to expect performance to match the rating system, this means that AMD expects the addition of a dual channel memory controller to more than make up for a halving of the cache.

The slight name change in equivalently clocked parts has had us wondering for a while if we would see the expected increase in performance. With an increase in rating of 100 points for the 3400+ and 3700+, we would expect to maximally see 2.9% and 2.7% increases in performance. Anything around the 2% mark will be enough for us to be comfortable with the new naming scheme, but we certainly don't want to see too many lower numbers.

Normally in testing, we consider a less than 3% margin to be essentially equivalent performance, but this time around we will be paying a little closer attention to any small increases in performance in order to determine whether or not this new performance rating is deserved.

The new FX-53 part number has obviously not changed, as its model number is dependant upon clock speed. We will also not be seeing as significant a performance increase from 940 to 939 pin platforms as upgrading to dual channel from single channel will have a higher impact on performance than moving from registered to unbuffered memory. On the 939 platform, the only performance factor that separates the FX series from the rest of the Athlon 64 line will be its 1MB L2 cache size. Of course, to help maintain its status as an enthusiast part, the FX series will also be completely multiplier unlocked.

But there is a caveat to that as well. With the advent of AMD's Cool'n'Quiet (which is similar in affect to Intel's Enhanced SpeedStep), motherboard makers who choose to implement the technology will be able to offer their users downwardly unlocked multipliers for the Athlon 64 platform. Being able to decrease the multiplier is very important for hardcore overclockers as much higher bus speeds (and thus RAM speeds) are attainable when the core multiplier can be lowered.

What's In A New Socket The Test
POST A COMMENT

38 Comments

View All Comments

  • gherald - Tuesday, June 1, 2004 - link

    Search for 939 on newegg.com folks, you will be pleasantly surprised! Now if we could just find a motherboard...

    I had been hopping this launch would bring the 754 prices down a bit to, say, $220 for a 3200 and $350 for a 3400, but it doesn't seem like that's going to happen quite yet what with 939 starting out at $500 for the 3500 and $700 for the 3800... *sigh* ... more waiting... perhaps prices will come down by the time true PCIe motherboards are availeable.
    Reply
  • amdfanboy - Tuesday, June 1, 2004 - link

    Go AMD !! Reply
  • nserra - Tuesday, June 1, 2004 - link

    "Everything here is graphics card limited even at 1024x768, but perhaps in the near future when we upgrade the video card we use in CPU and motherboard tests..." i have said this at xbit site and I say it here again!
    What about lowering games resolution and details it may help! There is a detail level in almost every game, it may help. You are testing a processor not the video card! I don't want benches in a processor review that limit the differences between processors.
    fx53 35 fps vs xp3000+ 34fps, what a difference!
    Reply
  • JGF - Tuesday, June 1, 2004 - link

    #22 while I certainly agree these new prices are too high I dont agree with the wholesale gutting of prices that you're recommending. AMD deserves some decent margins, they shouldnt have to give their product away all the time. Thats unhealthy business and has really hurt amd in the past. I want a healthy amd and for that they are going to need some fatter margins on some sku's. Reply
  • RyanVM - Tuesday, June 1, 2004 - link

    Found a typo on page 13: "Winstones hare usually very static..." should be "Winstones are usually very static..." Reply
  • XRaider - Tuesday, June 1, 2004 - link

    What the heat issues with these newer AMD cpu's? I believe I read on that French site that the new AMD's are putting out alot of thermal wattage! 100+ Can anyone confirm this? I believe the P4 3.4 puts out around 102 - 104 watts! That's alot. Reply
  • AtaStrumf - Tuesday, June 1, 2004 - link

    I found a couple of typos if anyone would care to correct them:

    p.13

    Workstation performance is more sensitive to memory bandwidth, and we do see a wider range in variation among the --3.2GHz-- (THAT WOULD BE 2,2GHz) processors in SPECviewperf.

    The pattern was the generally the same fastest to slowest of 939-949-754 (THAT WOULD BE 939-940-754)

    p.14

    Since we have found the performance of the Dual-Channel Socket 940 and the Single-Channel 754 to be close when hey (THEY)ran...

    Anyway these new S939s suck a$$. Well actually their prices do. Here's what I suggest: retire Athlon XP socket A, introduce it as Socket 754 but only higher models, price 20% up, bring S754 down 33% and S939 down 50%, retire FXs. These prices now are insane.

    AMD are you listening? Of course not.
    Reply
  • Viditor - Tuesday, June 1, 2004 - link

    "i'll be getting a Dual Channel for sure when the arrive. Pair that with a nice new X800 XT from ATI and i'll be sitting pretty with the flexibility of upgrading for awhile"

    Horses for courses I guess...I'll be getting one too, but I think I'm going nvidia because they appear to have a better handle on 64bit drivers...
    JMHO
    Reply
  • vedin - Tuesday, June 1, 2004 - link

    Sure would be nice if they released something more along the lines of a 3000-3300+ for 939 this year. Maybe then my brother can finally be nice and justified with an upgrade without having to spend a lot. Reply
  • Icewind - Tuesday, June 1, 2004 - link

    Hmmm, well i'll be getting a Dual Channel for sure when the arrive. Pair that with a nice new X800 XT from ATI and i'll be sitting pretty with the flexibility of upgrading for awhile.

    Thanks again AMD, im anxious to get out of this P4 setup I have now.
    Reply

Log in

Don't have an account? Sign up now