Processor speeds 3

[sweevo]

Hi,

Can anyone give me any quantative advice on the difference between an Athlon XP 2.5GHz and Athlon XP 3GHz?

2.5 GHz systems are within my budget, 3 GHz are really pushing it. For example, two systems I'm looking at have the above processors (this is the main, but not only, difference) - the latter for about £150 more.

Is the difference really noticable? Would I be better pushing my budget to get the higher spec?

Thanks

 

[edemiere]

Well, I would personally say without tossing numbers around that the 2500 would serve your needs nicely.

Few things to consider though: (in no particular order)

(1) Get a board that supports 400FSB (so you could upgrade to a 3000 or 3200 that use 400FSB)?!
(2) Make sure the 2500 is 333 bus (so you could get as high as a 3000 CPU later if you chose)
(3) Make sure the memory you get is PC3200? (this supports point #1)

I guess in the end, it's all a matter of cost and what exactly you want to do with that hardware.

I am more for getting your essentials out of the gate to allow yourself flexibility later (i.e. getting a motherboard that supports the 400FSB so you could max out the CPU at a later date when they get more affordable).

Having flexibility in hardware is always goal #1 for me. I set out to decide on a few fundamentals like motherboard, make sure it has all the features I want while allowing me the ability up get better upgrades later.

That's just how I do it though.

Hope some of that advice helps.

Cheers!

 

[edemiere]

Just read this, thought I would pass it along:

newegg.com is blowing out AMD Athlon XP 2500+ Barton retail box processors at $84 w/free shipping.

Not sure what that translate to in your currency, but you might check it out.

Cheers!

 

[price351]

Buy only what u need as it will all be pretty useless after a few years

 

[crazy888s]

That AMD Athlon XP 2500+ for $84 is exactly what I have. It only runs at 1.83 GHz though (i have it overclocked to 2.1GHz though with a 400FSB, which kinda relates to what edemiere was saying. It flies.)...But are you talking about the Athlon 2500+ that runs at 1.8GHz or an Athlon processor that runs at 2.5Ghz? Dont let the labeling system fool you! Either way, I'd go with the Athlon... unless you are a crazy, insane, 24/7 hardcore gamer and you have to have ever spec turned all the way up and want your game run just a little better....

 

[paparazi]

edemiere, Barton core XP2.5+ CPU's are 333fsb??????
crazy888s, not sure what you mean about clock speeds.
All XP CPU's are sold on AMD's numbering system, this is a percieved performance figure when compared to an equivelant Intel P4 and not there true clock speed (but then you already new that)
Back to the original poster (an XP2.6+ is better value at the moment than the XP2.5+) and You always pay a premium for the "fastest available" CPU's, so NO it's not worth the extra $150 for the XP3.0+ (performance advantage is very slight)
Martin

Replying helps further our knowledge, without comment leaves us wondering.

 

[crazy888s]

PAPARAZI-
yes...the "barton" core xp 2500+ has a 333fsb....all Bartons do. the athlon "thoroughbred" xp 2600+ does not though! Every thoroughbred runs at 266MHz front side bus, which in my opinion makes the Barton 2500+ a better processor than the thoroughbred 2600+ even though the AMD numbering system has the 2600 higher. When I'm talking about clock speeds, I'm talking about the actual processor speed of the athlons are not what the numbering system makes them to be (like you said too). For example, the Barton 2500+ only has a processor speed of 1.83GHz. The Thouroughbred 2600+ has a processor speed or 2.0GHz. Sweevo was talking about the "Athlon XP 2.5GHz and Athlon XP 3GHz", which makes me wonder if he's asking about the Athlon XP 2500+ and 3000+ because they dont run at 2.5GHz and 3GHz like he might think, but they run instead at 1.83GHz and 2.17GHz respectively.

 

[paparazi]

Just to put the record straight, only a few of the first XP2.6+ CPU's were 266fsb Thoroughbred core, that soon changed, all OEM and retail XP2.6+ 's are now 333fsb and have been for several months now, infact you would have considerable trouble locating a Thoroughbred XP2,6+ unless it was old stock.
Barton XP2.6+ 333fsb 2083mhz CPU the Thoroughred version had a very slightly higher clock speed but obviously didn't perform as well due to it's 266fsb.
Martin

Replying helps further our knowledge, without comment leaves us wondering.

 

[edemiere]

crazy888s

Small breakdown to try and clear things up. I think I covered some of the most

promonent CPU's, though there were some varying "sub-model" number changes (i.e.

revision 6, 8 and 10) within the processor history. This list is by no means

complete, but will demonstrate some of the varying differences as they changed CPU

cores which I chose to group by.


CPU MODEL NAME ACTUAL FSB L1 L2 CORE
SPEED SUPPORT CACHE CACHE TYPE
============== ====== ===== ==== ====== ==========
AMD Athlon XP 1500+ 1.33GHz 266 128K 256K Palomino
AMD Athlon XP 1600+ 1.40GHz 266 128K 256K Palomino
AMD Athlon XP 1700+ 1.47GHz 266 128K 256K Palomino
AMD Athlon XP 1800+ 1.53GHz 266 128K 256K Palomino
AMD Athlon XP 1900+ 1.60GHz 266 128K 256K Palomino
AMD Athlon XP 2000+ 1.67GHz 266 128K 256K Palomino
AMD Athlon XP 2100+ 1.73GHz 266 128K 256K Palomino

AMD Athlon XP 1700+ 1.47GHz 266 128K 256K Thorobred A
AMD Athlon XP 1800+ 1.53GHz 266 128K 256K Thorobred A
AMD Athlon XP 1900+ 1.60GHz 266 128K 256K Thorobred A
AMD Athlon XP 2000+ 1.67GHz 266 128K 256K Thorobred A
AMD Athlon XP 2100+ 1.73GHz 266 128K 256K Thorobred A

AMD Athlon XP 2400+ 2.00GHz 266 128K 256K Thorobred B
AMD Athlon XP 2600+ 2.13GHz 266 128K 256K Thorobred B
AMD Athlon XP 2600+ 2.08GHz 333 128K 256K Thorobred B
AMD Athlon XP 2700+ 2.167GHz 333 128K 256K Thorobred B
AMD Athlon XP 2800+ 2.25GHz 333 128K 256K Thorobred B

AMD Athlon XP 2500+ 1.83GHz 333 128K 512K Barton
AMD Athlon XP 2800+ 2.08GHz 333 128K 512K Barton
AMD Athlon XP 3000+ 2.167GHz 333 128K 512K Barton
AMD Athlon XP 3000+ 2.1GHz 400 128K 512K Barton
AMD Athlon XP 3200+ 2.2GHz 400 128K 512K Barton

Hope this layout shows you some clarification on CPU model numbers and at what

speeds they operate and how much cache is on each CPU.

Again, this is not a 100% inclusive list, because I tossed it together in a hurry.

Cheers!

 

[ceh4702]

I think the 400 Mhz processors also have a larger L2 Cache which makes them even faster.

You have to watch out for the differences.

The Thoroghbread core goes to a 333 Bus at 2600+, 2700+, and has 256K L2 Cache.

The Barton core has 512k L2 cache. The XP2500+ and XP2800+ run at a 333 Bus Speed and the XP3000, and XP3200 run at a 400Mhz Bus.

The 2800 runs $173.00
The 3000 runs $275.00
The 3200 runs $446.00

It might be worth it to purchase a Barton Core 2500 or 2800. However you could opt to go with an Intel motherboard at 800Mhz bus and 2.4CGig 800 Mhz Bus which runs at the same speed as a XP2800. The Intel P4 2.4C has a good price for the money.

Retail Prices
2.4C $173.00
2.6C $216.00
2.8 $268.00

There is a price advantage for Intel in this range!

If you do not like my post feel free to point out your opinion or my errors.

 

[Nyg]

To edemiere

What about the Athlon XP 2200+, hee hee

 

[cdogg]

Nice list edemiere!


~cdogg
[tab]"The secret to creativity is knowing how to hide your sources"
[tab][tab]- A. Einstein

 

[edemiere]

Oh darn, I left off the 2200+ off the list, my bad.

Sad thing is I have one at home too, lol.

Cheers!

 

[Nyg]

To Edemiere

Only having some fun,

Good List!

 

[crazy888s]

haha...well i obviously didnt realize the Thorobred design had been upgraded! I guess it has been a couple months since I really looked into it. That is a nice list by the way. Thanks for clearing that up.

Heres a little personal tip for anybody that overclocks!
If anybody that is semi-advanced with assembling computers is looking for a great processor for cheap, the AMD Athlon XP 2500+ 1.83GHz is like only $84. If you buy some PC3200 DDR RAM that runs at 400Mhz, and a board that supports 400MHz FSB (especially if it's Dual channel), the Barton 2500+ can easily be overclocked to run at 400Mhz flawlessly. I myself have this and have read so many people confirming this processor to be a great overclocker. BIOS and SiSandra will identify it as AMD Athlon XP 3200+ 2.2GHz 400MHz FSB and Sandra tests show great improvements with it. I've had this setup for about 2 months now (i know that's not very long) and it has not locked up, crashed, had any heat problems, or shown any signs of stress. And the price difference between a 2500+ 333FSB and 3200+ 400FSB is $435-$84=$351!!!!!! Now if youre a cheap guy like me...that will make you proud.

 

[ceh4702]

The XP2200+ and the XP2400+ run at 266 Bus and are an excellent bargain if you already have a motherboard that supports them.

I put together an Asus A7N8X Deluxe and a XP2400+ with a Sapphire Radeon 9000 for my son for college in the Fall and I thought it was a pretty fast running setup. Very easy to get running with WinXP.

If you do not like my post feel free to point out your opinion or my errors.

 

[paparazi]

Nice list edemiere, guess I was wrong thinking the 333fsb version of the XP2.6+ was a Barton.
Cheers.
Martin


Replying helps further our knowledge, without comment leaves us wondering.

 

[edemiere]

Ok, I found the information on the AMD vs Intel and why AMD doesn't benefit as much as Intel with the large CPU caching.

This is a LARGE article and unfortunately I no longer have the link that it came from. All I have it in is an email that I had sent a colleague a while back.

Please forgive the long post. Read on:

What are the Benefits of a Larger Cache?
Bigger is better right? So a 512KB L2 cache must be better than a 256KB one - after all, AMD wouldn't spend 17 million transistors for no gain. Although it's very true that a larger cache is generally beneficial, the real question is how beneficial and in what situations. To answer that question, we should have a quick lesson in caches and what makes them so useful.

Think of a cache as a bridge between two entities - a slower and a faster one. In this case, the cache we are talking about is part of a multilevel cache system and it helps to bridge the gap between the CPU and main memory.

It's no surprise that main memory runs significantly slower than today's CPUs. Not only does memory run at significantly slower clock speeds (e.g. 200MHz for DDR400) than today's CPUs, but main memory is physically located very far away from the processor. Our multi-gigahertz CPUs have to waste well over 100 clock cycles to retrieve data from main memory as their requests must cross over slow front-side buses, through an external memory controller, to the memory and back. Making this trip can wreak havoc on performance, especially for CPUs with very long pipelines, as these pipelines generally remain idle if the data necessary to populate them has to be fetched from main memory.

The idea behind a processor's caches is that you store important data in these high speed memories (now located on the processor's die itself), so that most of the time, your CPU doesn't have to make the long trip to main memory. The reason caches are split into multiple levels is because the larger your cache is, the longer it takes to fetch data. Therefore, it ends up being that having one smaller but very low latency cache combined with a larger and somewhat higher latency (but still significantly quicker than main memory) cache provides the best balance of performance in today's microprocessors. These two caches are the Level 1 (L1) and Level 2 (L2) caches you hear about all the time.

Caches work based on two major principles - spatial and temporal locality. These two principles are simple; spatial locality states that, if you are accessing data, then, the data around it will be accessed soon, and temporal locality states that if you are accessing data, chances are that you'll access that same piece of data again. In practice, this means that frequently accessed data is kept in cache, as well as data physically around it. Since caches are of relatively small sizes (rightfully so, it would be cost and performance prohibitive to have main memory-sized caches), the algorithms they use to make sure that the right information remains in the cache is even more critical to performance than the sheer size of the cache.

With Barton, AMD left their L1 the same as before, but increased their L2 cache size by a total of 256KB. AMD didn't change any of the specifications of the cache (e.g. it is still a 16-way set associative L2 cache) Luckily, AMD increased the cache size without sacrificing access time, but where will the added L2 cache help?

Let's look at those two principles we mentioned before, spatial and temporal locality. If an application's usage pattern does not abide by either one of these principles, then it doesn't matter how much cache you add, the performance will not improve. So what are some examples of applications that are and are not cache-friendly?

For starters, let's talk about things that don't abide by the principle of temporal locality - mainly multimedia applications, more specifically - encoding applications. If you think about how encoding works, the data is never reused, simply encoded on a bit-by-bit basis and then the original data is never touched again. At the other end of the spectrum, we have things like office applications that happily abide by the principle of temporal locality. In these sorts of applications, you are often re-using data, performing very similar tasks to them over and over again and thus making great use of larger caches.

The principle of spatial locality applies to a much wider range of applications, including multimedia encoding applications because of the fact that data is generally stored in contiguous form in main memory and is thus very cache-friendly. Spatial locality is why you will see some improvement from larger caches even in applications that don't exhibit much temporal locality.




AMD's Cache Benefits vs. Intel's Cache Benefits
All caches are not created equal and thus you should not expect AMD to benefit as much as Intel did from going to a 512KB L2 cache. Intel follows a much more conventional L1/L2 cache architecture that uses what is known as the inclusive principle; the inclusive principle states that the contents of the L1 cache are also included in the L2 cache. The obvious downside to this is that the L2 cache contains some data that is redundant that the CPU will never use (if it needs it, it will get it from the faster L1 cache). From the CPU's point of view, an inclusive cache just means it has less room to store its much needed data in, but from the standpoint of the rest of the system an inclusive cache does provide one advantage - if data is updated in main memory (e.g. through DMA), the memory controller only has to check the L2 cache to update data, and there is no need to check L1 for coherency. This is a small but important benefit to an inclusive cache architecture.

The opposite, obviously, is a cache subsystem that follows the exclusive principle - such as the Athlon XP's cache. In this case, the contents of the L1 cache are not duplicated in the L2 cache, thus favoring cache size over the added latency of checking for two levels of cache coherency in DMA situations. The exclusive approach makes much more sense for AMD, considering the Athlon XP has an extremely large 128KB L1 cache that would be very costly to duplicate in L2 (compared to Intel's 8KB L1 Data cache that is easily duplicated in L2).

Both architectures have their pros and cons, but are best suited for the particular CPU we are talking about. Recognizing the differences, however, helps us understand why AMD will benefit differently from Intel when it comes to the 256KB to 512KB cache leap, but this still isn't the full story.



What about the 400MHz FSB?
After Comdex, the word on the street was that AMD would be moving Barton to a 400MHz FSB in the near future but that the CPU would debut with a 333MHz FSB. As you can tell by today's release, we are still dealing with 333MHz FSB CPUs, but what is there to be said about the potential impact of a 400MHz FSB?

A larger L2 cache means that Barton has to go to main memory much less often (assuming that our applications do abide by the principles of spatial and temporal locality), which means that it has to send requests and receive data across the FSB much less frequently compared to an identically clocked Thoroughbred.

Since Barton is being launched at speeds slower than the fastest Thoroughbred, the immediate need for a 400MHz FSB isn't apparent - remember, FSB traffic should be reduced by the larger L2 cache. However, as Barton ramps up in clock speed, the move to a 400MHz FSB may become more appetizing as higher clocked Athlon XPs will require data at a faster rate to keep their pipelines filled.

So today, Barton would benefit less from a 400MHz FSB than the Thoroughbred core, which isn't much at this point either. Remember that the main benefit of the 333MHz FSB was latency reduction because of the fact that the FSB and memory bus were finally operating at the same clock speed once again, and not because of the increase in FSB bandwidth.

 

[greyted]

edemiere,
Thank you for that, superb information.


Ted

"The difference between a misfortune and a calamity is this: If Gladstone fell into the Thames, it would be a misfortune. But if someone dragged him out again, that would be a calamity."
Benjamin Disraeli.

 

[ceh4702]

XP2500 is a 333Mhz CPU Bus and has 512k L2 Cache.

XP3000 is a 400Mhz CPU Bus and has 512k L2 Cache.

The motherboard requirements are different for each. Makes sure the motherboard supports a 400Mhz or 333Mhz bus depending on what you decide. The 400 Mhz Bus can take better advantage of available memory Bandwidth, but has a pretty high pricetag.

I recommend a motherboard that supports the 400Mhz CPU Bus and the DDR400 Memory. This is probably as far as the non-opteron CPU's will go. This would provide an upgrade possibility in the future to XP3200+. For Asus A7n8X you may want to make sure that you get Rev 2.0. Get the latest revision that supports DDR400.

I have heard rumors of the DDR500 coming out soon, but I do not know what kind of motherboard that will be for. Since it is not out now that is not that important.

If you do not like my post feel free to point out your opinion or my errors.