Gentoo Archives: gentoo-user

From: James <wireless@×××××××××××.com>
To: gentoo-user@l.g.o
Subject: [gentoo-user] Re: Question about flakey RAM
Date: Fri, 30 Jan 2015 21:06:57
Message-Id: loom.20150130T214323-560@post.gmane.org
In Reply to: Re: [gentoo-user] Question about flakey RAM by Volker Armin Hemmann
1 Volker Armin Hemmann <volkerarmin <at> googlemail.com> writes:
2
3
4
5 > > I let memtest86+ run overnight and it found zero memory errors.
6
7 > Maybe it really operated in the range of allowed tolerances - and those
8 > were never crossed with memtest as a very light system load.
9
10 Manufacturers and designers of ram have sophiticated and expensive
11 systems to test ram. When and where to set the "cut off" for acceptable
12 and garbage memory, is a fluid call at most companies. Paying the high
13 price for the best ram does not ensure an outcome, but statistically
14 it moves up the odds favorably.
15
16 > But with an OS booted, the CPU, graphics solution, harddisks all sucking
17 > power like mad, your mainboard or PSU might not be able to deliver as
18 > stable currents as the specifications demand. Some memory is more
19 > tolerant than other.
20
21 Along with increases in power draw comes differential heating. Heat is the
22 enemy of all electronics. Add to this the stealth phenomenon of
23 "wait-states" [1] and it is hard to predict ram behavior, let alone what
24 is acceptable and what "fails". We, as users, merely judge the ram
25 by the fact that the system keeps running and does not crash as OK.
26 That's not really how processors, busses and SS memory works, but it
27 is all we have to judge memory performance.
28
29 Memtest is great, but it's really like using sharpened animal bones as
30 surgical scalpels. Version 5 [2] is better, but still it is only a very
31 modest tool to a very complex and transient problem; which is very sensitive
32 to the quality of the volage/current, as Volker pointed out,
33 as well as the differential heating effects inside your PC chasis. That's
34 why the gaming systems today create turbulent air flow inside the chasis.
35 I use water coolers, sandwiched inside (2) fans to cool my 4GHz amd-8350
36 CPUS. The coolder the better for electonics to about few degrees above
37 freezing. But, also humidity plays a roll on cooling electronics.
38
39
40 hth,
41 James
42
43
44 [1] http://en.wikipedia.org/wiki/Wait_state
45
46 [2]
47 http://forum.canardpc.com/threads/84663-Memtest86-is-freezing-while-running-test-7