[ale] 2 questions memory related
Greg Clifton
gccfof5 at gmail.com
Mon Jun 20 16:40:13 EDT 2011
I can't pick a "best" brand of RAM, but Kingston, Crucial, Wintec
and Geil, among others are all good brands.
Kingston is absolutely a good brand and in fact is the largest manufacturer
of memory products (this includes SSDs, Thumb Drives as well as memory
modules). They have a vast array of product quality (or perhaps more
branding) grades and do a lot of OEM manufacturing (DELL, HP, etc. don't
make their own memory modules, you know). But I have had good success even
with their Value RAM line. Most manufacturers have more than one product
grade and many of them have "Value" products by whatever name. The deal
there is that Value RAM meets a certain specification but can be made from
different chips depending on who has the best price at the time of purchase
by the manufacturer. "Server Class" memory, by whatever name it is sold
under generally (and esp. for a certified part) has a BOM that cannot be
changed for the production life of that memory module. I.e. "Value" product
could be made with Micron chips this week and Samsung or Hynix next week,
but a "Server" product is made of the same PCB and chips for as long as that
particular part number is in production (i.e. as long as those chips are
available). This provides more "certitude" to borrow a recently popularized
word that you can upgrade your server RAM in the future with no timing
issues. This and the certification expense is also why server RAM will cost
more than a "Value" product. Not that the "value" isn't perfectly good RAM
for a given build at a certain point in time, but you may not be able to
exactly match the timing with the next purchase.
HTH,
GC
On Mon, Jun 20, 2011 at 9:45 AM, Scott Castaline <skotchman at gmail.com>wrote:
> On 06/19/2011 09:23 AM, Greg Clifton wrote:
> > I've been selling/building PCs for over 20 yrs and I can tell you that
> > modern memory is way better than it used to be. Not directly related
> > to Moore's Law but linked to it as a result of improvement in process
> > control & machinery used in making the RAM. BTW, Apple never used
> > parity RAM in their PCs (probably do in their servers, esp the Intel
> > based stuff but have 0 experience with those) but IBM PCs did. This
> > was supposedly to increase accuracy or at least to trap errors.
> > However, it turned out that the biggest source of RAM errors was from
> > radioactivity in the ceramic that the chips were packed in. Once
> > plastic/epoxy packaging was developed, RAM errors went WAY down. These
> > days you never see parity (now know as ECC) RAM except in servers and
> > it is generally associated with REGISTERED memory in machines with
> > >24GB of memory. Both Intel Nehalem family chips (Current generation
> > Xeons and i3, i5, i7) and AMD 6100 & 4100 series CPUS w/ built in
> > memory controllers can support either REG (not so much with i3 and i5
> > and at least some of the i7) or NON-REG RAM. REG is usually required
> > for installations over 24GB because of bus loading.
> >
> > Also, as a rule of thumb, it is OK if your memory can run faster than
> > your memory clock, but not the reverse. I don't know it for a fact,
> > but suspect that most modern memory has much wider tolerances than
> > what it is sold as which is partly responsible for the fact that we
> > rarely see memory errors on new systems. You are quite right regarding
> > overclocked systems needing better matched parts, and of course better
> > cooling (think water cooled, although at a recent vendor showcase the
> > Kingston rep said that the water cooled memory that they sell is
> > mostly for show and that their modules with metal fins actually cool
> > better).
> >
> > The main reason for matching RAM was to have matched modules in each
> > memory channel back when systems had dual memory channels. Current
> > systems have either dual, triple or quad channel memory and memory
> > modules should still be installed in sets of 2, 3, or 4 accordingly.
> > Now in a dual processor system, you could have different spec RAM on
> > each CPU with no problem since each CPU has its own memory controller.
> > But as a practical matter in a new build, that would probably never
> > happen.
> >
> > One final note, again due to bus loading, when a modern system is
> > loaded with memory modules, the memory clock automatically slows down
> > to make the system more reliable.
> >
> >
> > On Sat, Jun 18, 2011 at 8:33 AM, Scott Castaline <skotchman at gmail.com
> > <mailto:skotchman at gmail.com>> wrote:
> >
> >
> >
> > On Fri, Jun 17, 2011 at 1:05 PM, Greg Clifton <gccfof5 at gmail.com
> > <mailto:gccfof5 at gmail.com>> wrote:
> >
> > The installing/replacing memory in sets is basically due to
> > older [but not too much older] motherboards ran dual channel
> > RAM [new Intel 2P and some 1P is Triple and AMD is Quad
> > Channel] and you don't want to mix RAM with different specs in
> > the same channel. Also, possibly the manufacturer figures if
> > one module failed it's 'partner' is apt to go soon so just
> > replace both instead of having two trouble tickets to deal
> > with stretched over several weeks.
> >
> > That part I've got, the pairing, what I had the impression of was
> > when you bought like 4 sticks like I had you had to buy all four
> > as a set, not just say buy a pair and then add another pair (same
> > exact one as the 1st pair) later to add on. It didn't make sense
> > to me unless if you're going to push things to the extreme with
> > overclocking and such, then you need "handpicked" components,
> > which for some reason I was under the impression that was what the
> > mfgs were saying for all cases. It was like when I worked at
> > Harris back in the late 70's they had developed a system code
> > named 2C which had it's clocking set up to push TTL to it's
> > extreme limit producing ECL speed (25nsec windows). All chips for
> > that system had to go through special screening for handpicking
> > for the 2C, this was the impression I had got of current memory
> > buying practices. I don't want to give the impression that I don't
> > understand that you have to buy in at least pairs and that all
> > sticks have to have the same specs. I personally would stick to
> > the same make/model as what I already have.
> >
> >
> > On Fri, Jun 17, 2011 at 12:24 PM, Michael B. Trausch
> > <mike at trausch.us <mailto:mike at trausch.us>> wrote:
> >
> > On 6/17/2011 12:11 PM, Scott Castaline wrote:
> > > Sorry for replying to a reply, but to Mike, htop is
> > showing 16
> > > incidents of mysql, whereas top is only showing 1. Each
> > incident is
> > > using 1.0% of memory. I also noticed several incidents
> > of kworker*
> > > running of which (about 20) I don't remember the %Mem
> > for each.
> > You're probably seeing all of MySQL's threads in htop.
> > They together
> > will still be using only 1% of the memory...
> >
> > kworker is a kernel thread, which has something to do with
> > ACPI.
> >
> > --- Mike
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org <mailto:Ale at ale.org>
> > http://mail.ale.org/mailman/listinfo/ale
> > See JOBS, ANNOUNCE and SCHOOLS lists at
> > http://mail.ale.org/mailman/listinfo
> >
> >
> >
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org <mailto:Ale at ale.org>
> > http://mail.ale.org/mailman/listinfo/ale
> > See JOBS, ANNOUNCE and SCHOOLS lists at
> > http://mail.ale.org/mailman/listinfo
> >
> >
> >
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org <mailto:Ale at ale.org>
> > http://mail.ale.org/mailman/listinfo/ale
> > See JOBS, ANNOUNCE and SCHOOLS lists at
> > http://mail.ale.org/mailman/listinfo
> >
> >
> >
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org
> > http://mail.ale.org/mailman/listinfo/ale
> > See JOBS, ANNOUNCE and SCHOOLS lists at
> > http://mail.ale.org/mailman/listinfo
> Sorry I didn't get to thanking everyone for the input. I didn't have
> access to my system for about 3.5 days and my wife kicked me off of her
> work laptop. But thanks for all the feedback, I do have one more
> question for Greg in what is your feeling for Kingston, still a good
> product?
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.ale.org/pipermail/ale/attachments/20110620/d3c9bb71/attachment-0001.html
More information about the Ale
mailing list