Re: AMD64-based laptops from HP/Compaq are crippled

From: alex goldman (hello_at_spamm.er)
Date: 07/05/05 

Date: Mon, 04 Jul 2005 23:19:07 -0700

Robert Klute wrote:

> On Mon, 04 Jul 2005 20:46:58 -0700, alex goldman <hello@spamm.er> wrote:
>
>>I've been researching my next laptop purchase, and whether it will run
>>Linux, and completely accidentally stumbled upon an alarming issue that
>>people need to be more aware about.
>>
>>Apparently (and if my understanding is correct), HP/Compaq disables
>>dual-channel memory access in Socket 939 motherboards, making CPU <-> RAM
>>communication slower, and overall performance less than what people would
>>expect when buying a system with the outward characteristics of what they
>>think they are getting.
>>
>>http://zv6000forums.com/viewtopic.php?t=148
>
> The laptops use the Turion chip.

Wrong. _Some_ of the laptops use the Turion chip (quite few as of this
writing, actually).

Regardless ...

> According to AMD, the Turion's
> integrated memory controller can use PC1600, PC2100, PC2700 or PC3200
> unbuffered DDR SO-DIMMs and has a maximum throughput of 3.2 GB/s.

Do you understand how dual-channel access works? You have 3.2 GB/s per
memory module, i.e. up to 6.4 GB/s. Dual-channel access is more, not less,
important when slow memory is used.

> So, explain to me what engineering in dual channel support is going to
> buy you. BTW, does any vendor manufacture dual channel compatible
> SO-DIMMs?

There is something you have in common with the NoNoBadDog