Which Intel Mobile Processor is best for floating point computational use?

[losemind]

Hi all,

My laptop is broken and I am seriously considering purchasing a new laptop. I mainly use the laptop to do all kinds of programming and scientific/numerical computations, including Matlab, C/C++, Fortran, Maple, Mathematica, etc. I am wondering if anybody can tell some experiences about speed performance of Maple on Core Duo Dual Core processors? Are the computations on these computers really faster?

I recall a few months ago I had tested a Monte Carlo program in Matlab on my friend's new Intel Quad Core (4 cpus). He paid $6000 for a desktop like that. The speed was not improved at all, compared to a single CPU.

I am wondering which mobile processor shall I buy for my specific applications? Does it support SSE3, and native support for complex-numbers, vectorized computations, and many other advanced features for floating-point and scientific computation?

Thanks a lot!

[TimP]

You would likely be more satisfied with Core 2 Duo rather than the obsolete Core Duo. Both support SSE3 and related features you mentioned, while Core 2 Duo also supports 64-bit OS. 64-bit OS should be advantageous for you, if you install 2GB or more RAM.
As you suggest, quad core has limited value for non-threaded applications, and is probably not yet viable for laptops.
Current C,C++, and Fortran compilers support OpenMP compilation for multi-core, including the C and C++ which come with current OpenSuSE 10.2, and also VS2005. In addition, Intel C++ and Fortran support auto-parallelization.

[losemind]

Thanks Tim,

My primary concern is speed for scientific computation.

For that people say desktop is better choice. They suggest me to lower my expectation(hence price) on laptop and buy desktop for computing.

So here are the budget planning:

1. A very lousy laptop + upgrade my existing desktop(P4 3.2GHz), which is actually repurchasing a new desktop;

2. Focus on a high end laptop + live with my current P4 3.2GHz desktop.

Which approach is the best in terms of cost and performance overall?

Thanks

[TimP]

I did myself replace a P4 3.2 desktop motherboard with a top end Core 2 Duo, keeping the old DVD and video. This certainly will outperform any laptop.

[losemind]

tim18:

I did myself replace a P4 3.2 desktop motherboard with a top end Core 2 Duo, keeping the old DVD and video. This certainly will outperform any laptop.

Is it possible?

The Core 2 Duo needs more power and the P4 3.2 desktop (I bought a Dell Poweredge 400sc with P4 3.2GHz) case will not be good that. I think you effectively bought a new PC, except probably you didnot change the keyboards, mouse, DVD and harddisk.

But what's the difference between teh Core 2 Duo on desktop vs. the Core 2 Duo on laptop? You think the speed will be very different, assuming I am using laptop with AC power continuously?

Btw, I've heard that the CPU on laptop will step down and get slower(cooler) during heavy compuations even when the AC is on and the power consumption and battery is not a concern? Is that true? If that is so, so laptop is definitely not suitable for computations...

[TimP]

You may be thinking of the Santa Rosa mobile platform, which can run at a higher clock speed when only one core as active. This would mean that the advantage of dual core is greater for the desktop CPU.

[steven-worley]

You can do both! Get a high end laptop, and a dock for it, and use your laptop as your main machine at home too, with full keyboard/mouse/screen.

A modern dual core Core 2 laptop has more than enough power even for professional development. It will spank your old Pentium 4 mercilessly.

Only thing to watch for when doing this, is get enough RAM (laptops tend to short themselves on RAM), and get a mini-dock so you can change from mobile to desktop mode instantly.

[levicki]

Here is how I see it:

• Desktop Core 2 Duo has 1066MHz and 1333MHz FSB. Laptop has 667Mhz or 800MHz FSB.
• Desktop Core 2 Duo can run as high as 3GHz, laptop cannot.
• Desktop machine can use quad-core CPUs, laptop cannot
• Desktop machine has DDR2-800 and DDR2-1066 RAM while laptop has DDR2-533 and DDR2-667.
• Desktop machine can have 10,000 RPM drive, laptop cannot.
• Desktop machine can have high-end video card with very powerfull GPU which can perform general purpose computations, sometimes many times faster than even quad-core CPUs. Cards with full 64-bit FPU precision are expected in November, needless to say, laptop cannot have high-end GPU due to serious power and heat constraints
• Laptops with more than 2GB of RAM are rare if not non-existent. Desktops can have 8GB or even higher with server/workstation boards.
• Laptop parts cannot be upgraded.

[losemind]

Here is one more thought base on my bitter experience:

My tablet PC, purchased 1.8 years ago. Died recently of video card failure. And because it is an integrated motherboard, I have to throw away the whole computer, including the fancy tablet part.

Based on this lesson, I guess I wouldn't choose to buy a high-end laptop at a much higher price premium. If you use a laptop as a computing machine, it is very failure-prone.