athlon64 vs athlon64fx vs opteron

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K

krzys

could anyone tell me main differences between these processors ? or
maybe lint to page where I can read about it ?

K.
 
could anyone tell me main differences between these processors ? or
maybe lint to page where I can read about it ?
Click to expand...

Hi,

well in simple terms I believe Athlon64's are the mainstream performance
CPU's, the AthlonFX is the flagship *megadon* cpu and the Opteron's are
designed to work in clusters (i.e: quite a few of them working in a
server/s).

Wayne ][
 
could anyone tell me main differences between these processors ? or
maybe lint to page where I can read about it ?

K.
Click to expand...

There are three flavors of Opterons, the 1xx, 2xx, 8xx. All have two
memory channels, use registered DIMMs and have three hypertranport buses.
The difference between the three is the coherency logic on the
hypertranport buses, the 1xx lacks any coherency logic, the 2xx has it on
one hypertranport bus and the 8xx has it on all three. The purpose of
coherency logic is to allow one processor to know what is in the cache of
another. The 1xx Opterons can only be used in single processor systems,
the 2xx Opterons in dual processor systems and the 8xx in systems with up
to 8 processors.

There are also three flavors of the Athlon 64, the 754 pin version, the
939 pin version and the 939 FX version. The original Athlon64 FX was a
rebranded Opteron 1xx, the current version of the FX is a 939 pin Athlon
64 with a bigger cache and the top clock rating. The 754 pin Athlon 64
has one memory bus, the 939 pin had two. The Athlon 64s are meant for
uniprocessor systems only, thus their hypertranport buses lack coherency
logic like the Opteron 1xx. The other difference is that their memory
controllers used unbuffered DIMMs. Unbuffered DIMMs have lower latencies
then Registered DIMMs so they give slightly faster performance. The
downside of unbuffered DIMMs is that each RAM on the DIMM adds a load
to the memory bus, as opposed to registered DIMMs which isolate the memory
bus from the individual RAMs. As a result unbuffered DIMMs can't be as
large as registered DIMMs. If you go to the Crucial website you will see
that you can buy a 2G Registered ECC DIMM but the biggest unbuffered DIMM
is 1G non-ECC and the biggest unbuffered ECC DIMM is only 512M.

The bottom line is that the Opteron is for servers which typically
have at least two processors and as much memory as you can possibly stuff
in them. The Athlon64 is meant for desktops which ususally have a single
processor and a smaller amount of memory. Using 512M DIMMs you can put 2G
on a 939 pin Athlon 64 which is plenty for a desktop, if you need more
than that then you need to move up to an Opteron server. A dual processor
Opteron, using 2G DIMMs, could have 16G of RAM in the system.
 
krzys said:
could anyone tell me main differences between these processors ? or maybe
lint to page where I can read about it ?
Click to expand...

Start on
http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118_9485_9487,00.html.
Then look at the information and comparison pages for each CPU series.

A few highlights:

The Athlon 64 comes in 754 and 939 pin versions, with varying cache sizes.
The "xx00+" rating will give you an idea of similarly performing processors.

The 64FX CPUs are large cache versions of the faster 939 pin A64s.

Opterons are mainly for multiprocessor machines (though there is an Opteron
14x series that is not multiprocessor capable). They use a 940 pin socket.

For price, look for the 754 pin A64s.

For gaming, look for the FX.

For dual-processor workstations, look for the Opteron 2xx.
 
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