|Originally posted by Kukailimoku
As for incompatible software, whether they're multi-threaded or not, if one thread or process isnt coded to prevent using up all physical resources within the processor, HT or not, all processing will stop until that single thread is done processing. That is the decreased performance i wanted to point out, which is a noted disadvantage of HT ( the processors inability to identify each threads physical resource requirements )
I do have a question....... i noticed that the specs for the 8890 mentioned requirements of 2 dimms for dual channel mode.... does that mean the laptops wont be using sodimms? If not, then Tanker-X my friend, you might be out of luck
The CPU can shelve a process and work on another one any time it wants to. There's nothing that the process can do about it (although most likely it can set a priority level so it only gets shelved for a 'more important' process). It is quite doable to design the CPU so that it can shelve any process, maing it impossible for a single process to lock it up. Even if it is possible for a single thread to lock up 100% of the CPU's resources, that's still 100% utilization, which is the goal of Hyperthreading.
Most program execution spends a lot of time with the CPU doing nothing. There are lots of situations that can cause the CPU to wait - fetching things from main memory (memory is much slower than today's CPUs), waiting for a conditional to determine which branch of code to execute, so on and so forth. (See this thread
for a discussion of pipelining and no-ops.) Hyperthreading, as I understand it, allows the CPU to maintain two threads in its execution memory (two program stacks, etc) and switch between them, so during one thread's no-op cycles it can work on the other thread.
Even programs that lock up single-processor machines still must have massive quantities of no-ops if the P4 pipeline is 20 steps. HT allows another program to execute during those no-op cycles when the first thread is waiting.
So, first, there is no decreased performance under HT. At the 'worst' - which means the most efficient program - it's just as fast as non-HT, and for the other 99.999% of the time it's faster.
'SODIMM' is a type of DIMM. When someone says 'DIMM', they could mean any type of DIMM, inclluding SODIMM. In the context of a modern laptop, they almost invariably mean 200-pin SODIMM as that is the kind of DIMM that fits in modern laptops. I assume that's the case with the 8890 specs.