Upgrading some parts - a few questions

Have found my CPU finally starting to bottleneck my system for gaming purposes, and upgrading the CPU (Athlon64 X2 6000+) will also require a motherboard upgrade (as the current one is a 4-5 year old AM2 one), and if the motherboard will be an AM3 one I'll also have to upgrade my memory from DDR2 to DDR3. I got a Radeon HD5770 half a year ago so the graphics card is sorted. I'd like to keep the total costs below 300€.

So, it all starts from choosing the CPU...

A friend of mine suggested getting an AMD Athlon II X4 640 (around 100€), but browsing for choices I stumbled upon AMD Phenom II X4 940 Black Edition, which seems to be a bit stronger than the Athlon (even without overclocking, which I don't intend to do), while the price is almost exactly the same. However, the Phenom is an AM2+ socket one, while the Athlon is AM3. The specs seem to be pretty much the same (both 3,0GHz etc.), but the Athlon has no L3 cache at all (the Phenom has 6mb, is this the main reason for the performance difference ?).

Now, that image gives me the impression the CPU will work in an AM3 socket...but there seems to be a general rule that AM3 CPUs work on AM2/AM2+ sockets, but not the other way around. So, would it work in an AM3 Motherboard or not ?

So, what should I do:
1. Assuming the Phenom works in an AM3 motherboard: get it, an AM3 motherboard and DDR3 1333Mhz memory.
2. Get the Athlon, an AM3 motherboard and DDR3 1333Mhz memory.
3. Get the Phenom, an AM2+ motherboard (like this one) and DDR2 800Mhz memory.

I'd think 1 would be the best choice if it works, but if it doesn't, 3 would give me the best performance right now (DDR2 vs DDR3 doesn't make much of a difference currently I hear), but 2 would be easier to upgrade after another 2-5 years but would cost ~50€ more now.

I have 3x1Gb of DDR2 (not sure about it's frequency, CPU-Z shows one at 200Mhz, one at 266Mhz, and one at 333Mhz) memory currently, and that brings me to another question: would it be a huge performance loss to stick with it and go with choice 3 without the new memory ? if not, that would be clearly the least costly route, which I wouldn't mind at all. Would also appreciate some tips regarding memory placement, I've heard it makes a difference which and how many slots are filled but don't know the details.

Also, a quick question on motherboards in general: how much of a difference do they make actually - more precisely, is it worth it to go for a 90-110€ one over a 60-80€ one ?

...I might have made some wrong assumptions here, I'm no expert and didn't want to spend all day confirming I got everything right so, feel free to correct me or even suggest other CPUs in the same price range.
7 answers Last reply
More about upgrading parts questions
  1. Its all a question of how much you want to spend.

    Phenom II and Athlon II both fit in an AM3 mptherboard
  2. What mobo do you have? Some AM2 mobos can take AM3 CPUS.
  3. ScrewySqrl said:
    Its all a question of how much you want to spend.

    Maybe, I probably could've made it a bit shorter, I basically need answers to a few things other than price that would affect my decision, these three being perhaps the most important:

    1. does the Phenom work in an AM3 motherboard ?
    2. Is my current memory so bad that sticking to it and getting an AM2+ motherboard and the Phenom is a bad choice ?
    3. the bit regarding motherboard choice in general.

    Anonymous said:
    What mobo do you have? Some AM2 mobos can take AM3 CPUS.

    Asus M2N (was mistaken about the age, it's 2,5 years old), can't find any more precise specification.

    Edit: to sum it up:

    Getting an AM2+ motherboard and the Phenom and using my current memory would cost 180€
    Getting an AM3 motherboard and the Athlon along with 4gb of DDR3 memory would cost 270€

    -> the latter doesn't seem to give a performance gain worth the price difference (I could be mistaken though, that's what I'd like to know), but it'd be easier to upgrade later on.
  4. the DDR3 vs DDR2 will give a 2-3% performance gain. a Phenom II X4 vs a same speed Athlon II X4 will get a 3-10% gain in performance (though is some applications and games that don't use the L3 cache well, the gain is actually zero), though either is well ahead of your 5-year old chip.

    Basically an Athlon II X4 in DDR2 would be around 10-15% slower than a Phenom II X4 at the same speed with DDR3, mixing them tends to be a wash to a slight gain for the Phenom II, depending on the app.

    Most Phenom X4s are faster than most Athlon II X4s however (the popular Athlon II X4s are 2.9, 3.0, and 3.1 GHz (635, 640, 645), while the popular Phenoms are 3.2, 3.4, and 3.5 GHz.

    if you are just upgrading, how long do you expect the system to last?

    If you're just going to build an all-new system, go for DDR3 either way

    I'd reccommend the DDR3 build with either Athlon or Phenom if you're building from scratch. For just an upgrade, both will sufficce on your current system
  5. Unless you really feel you can't wait any longer, I'd suggest waiting a few months. Both Intel and AMD are coming out with a new generation of chips (Sandybridge and Bulldozer) in the near future.

    Whether or not you choose to upgrade to these options (both would require moving to DDR3), they should drive the price of current processors & mobos down a little bit. It might also allow you to save up a little more.
  6. Thanks for the responses. Looks like I'll be going AM3 all the way then, now it's down to choosing between the 105€ Athlon II X4 640 and the 145€ Phenom II X4 955 BE. The main difference is still the L3 cache, which doesn't seem to make a really noticeable difference in most games (Left for Dead being an example of where it does based on this article), but it's impact is probably going up rather than down in the future ?

    edit: apparently the stock cooler in the Phenom is extremely loud, anyone have any experiences with it ? That's enough to tip the scales towards the Athlon for me, with such a price difference already I have no interest in buying a separate cooler for it (as I don't intend to overclock either).
  7. I'm pretty sure you can squeeze in a Phenom by selecting carefully the mobo/RAM. So you should take into account the whole deal not just the CPU.
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