Re: Improving performance: RAM or CPU speed (was: Re: New RAM, does Debian has a tool to benchmark?)

[rhkramer@gmail.com]

On Saturday, April 11, 2020 09:39:06 AM deloptes wrote:
> rhkramer@gmail.com wrote:
> > I think my bottleneck these days is again RAM

> Look at the L1 L2 L3 cache. Many people underestimate this
> 
> here are two examples from different pcs
> 
> # lscpu | grep cache
> L1d cache:           16K
> L1i cache:           64K
> L2 cache:            2048K
> L3 cache:            8192K
> 
> 
> # lscpu | grep cache
> L1d cache:           32K
> L1i cache:           32K
> L2 cache:            256K
> L3 cache:            6144K

Thanks for the reply -- interesting.  

Two of my machines (Wheezy and Buster) don't have L3 cache, my Jessie machine 
does.

I see varying definitions / explanations of L3 cache -- some say it is on the 
CPU die, and some say it is on the motherboard (but, in either case, one level 
further away from the CPU(s) (mcow).)

And, also in either case, not easy to upgrade short of replacing the CPU or 
motherboard.

RAM is still (to me) the most cost effective upgrade to an existing system.

(I guess I could mention that I don't play games, so video performance is not 
a key for me (and, when I do / did play. games, video performance was not a 
key -- games like FreeCiv and such).

I am considering a new machine at this time, a laptop with a good docking 
system (I'm looking for one with a USB-C port) so that I can easily undock it 
and take it to meetings, but use it at home for development with GCC 8 (or 
high 7) -- I want to do some work on a program (scintilla) that now uses 
features of C++ versions 11, 14, and 17.  (And I was thinking of taking the 
laptop to meetings where I might get help, but who knows when any such 
meetings will take place again.)

(I actually bought a machine (mail order that advertised a USB-C port but have 
to return it as it doesn't have a USB-C port.)

I guess I should say that I don't have objectional performance with any of the 
machines I have -- well, maybe I should take that back -- I keep the Wheezy 
system as my daily driver for several reasons -- including laziness, but also 
it seems better performance with kmail and firefox.

When I have as few as 10 to 15 tabs open on the Firefox on my Jessie system, 
Firefox crashes (I mentioned in a previous post in this thread having a 
thousand or more tabs "open" in Firefox on Wheezy with minimal problems -- yes 
occasional crashes (maybe once every 2 to 4 weeks?), but I couldn't come near 
that on Jessie, and I expect the same problem on Buster.

I guess that is all related to Wirth's law (and variations, Gates', ...).