RTW does not directly benefit from HT.
Intel implemented HyperThreading as a variation of Simultaneous Multi-Threading (SMT). Some applications can run more efficiently if they're coded into a series parallel tasks called threads. XP and Linux, e.g., can then schedule those threads to operate on each of a system's two or more CPUs (or cores). HyperThreading basically fools the OS into thinking it's hooked up to two processors, when in fact there is only one. This allows two threads to be run in parallel, both on separate 'logical' processors within the same physical processor. The OS sees double through a mix of shared, replicated and partitioned chip resources (e.g., registers, FPUs, and cache memory).
But... a single instruction thread only uses about 35 to 50% of a processor's available resources, and running a second 'virtual' thread (HyperThread) allows those otherwise idle circuits to be do some work. That means, for example, if one thread is busily computing a list of integer values, the floating-point unit (FPU) is free work on a second thread. The catch is that in reality, the CPU labor cannot be smoothly and efficiently divided, and sadly the best HyperThreading can do is increase certain (very limited) application performance by about 2% to 25%.
HyperThreading allows some applications are already multi-threaded to benefit, particularly business users can run the most demanding desktop applications simultaneously, and keep a semblence of system responsiveness. In gaming, intel sometimes combines HyperThreading with Dual core, which in theory allows PCs to handle 4 threads at once. But in reality, at this time, you can basically run different apps, like making an MP3 and playing a game and scanning for viruses, and more of the CPU capability is used. But the game itself does not take advantage of this division of labor, and in fact, certain glitches can occur (a reality streneously denied by some people). But the glitches are results of the software and the overhead processes, not of a faulty CPU.
So the bottom line is that HyperThreading is not much benefit in a practical sense for gamers today, including Rome - Total War. The AMD 64 line of processors are far far more efficient than the current crop of Intel processors, particularly for gaming. HyperThreading is basically more hype than help. Dual-core has real promise, but developers are not yet caught up, particularly in gaming. ATI just released a driver (5.12) that evidently splits the bloated fluff code (stuff that does not do video driving) to a 2nd thread, which results in improvements of 5 to 20%. However, I'll say that the fluff code should be minimized for gaming in the first place, and the game itself should use core#2 (or CPU# 2 for dual-CPU machines). The HyperThreading 'virtual cores' are not at all worth it for most people, including gamers (IMHO).
Last summer, Tom's Hardware Guide (THG) said,
Quoted from Tom's Hardware Guide comparing dual-core AMD to Intel dual-core, hyperthreading:
"The Pentium 840 EE has no chance when running a single application on Windows XP - the Athlon 64 X2 4800+ has up to 30% better performance . Here, even hyperthreading doesn't help.
However, if you are running multiple apps, on an Intel dual-core, hyperthreading CPU (in effect, 4 cores), and run software like buisines and engineering and video editing, etc., then the 840EE dual-core, hyperthreaded Intel CPU outperforms the Athlon 64 X2 4800. For games, it is inferior, by a huge margin. The intel, at full gaming load, also consumes 342 watts, vs AMDs far less 269 watts.Dual-CPU: Very good. Worth it for anyone who can afford it. Cheaper than Dual-core.
Dual-Core: Very expensive, will drop in price radically during next year, developers will not catch up until 12 to 18 months from now, according to MS.
HyperThreading: Not worth it (my opinion) for average users and gamers, mainly because the Intel CPU is itself inferior to the mighty Athlon64s. It can be worth it in the right environment, however... but not for RTW.My recommendation: The AMD runs games about 15 to 30% better (Athlon 64 X2 4800 vs Intel 840EE, on identical systems). If you have a choice, definitely get the AMD Athlon 64, not an Intel, for gaming (at this time and in the forseeable future). Note: HyperThreading is NOT the same thing as HyperTransport!! The latter is a manufacturer-neutral specification of high-speed chip communication protocols and methods: HyperTransport is worth it and you should make sure your chip has it. EDIT: added THG info.[This message has been edited by Wartrain (edited 12-18-2005 @ 05:37 PM).]