Originally posted by: rz
I'm currently building a system based on the P35-DS3R mobo. The mobo supports 800 and 1066 DDR2. I'm aiming to have an E8400 OC'd to 4GHz in this board. I've never really OC'd before so I'm not sure which to get. I've read if your going to OC you should have 1k+ but I also see folks with systems built around 800. The reason I ask is this is a budget build ATM and I see on newegg the 800 is alot cheaper. Does the brand of the RAM matter? It seems alot of folks favor GSkill and Ballistix, do these brands OC best?
Sorry for the novice questions.
Well it looks like (quick internet search) the E8400 has a maximul of 9X
multiplier. That means that 4GHz CPU speed using that best (maximum)
multiplier will mean you'll have this core clock: 4000/9 = 444MHz.
The P35 cannot (AFAIK) run the memory SLOWER than that core clock, i.e.
1:1 is the SLOWEST CPURAM multiplier you can use.
So thus a 444MHz *input* clock (to both the CPU and the RAM at 1:1)
is the SLOWEST RAM speed you could possibly use at 4GHZ CPU speed.
Since it's DDR2 the RAM doubles that, so 444MHz * 2 = 888 MHz DDR2 speed,
minimum, at 4GHz with that x9 CPU multiplier.
So assuming that I'm correctly seeing the x9 multiplier for your CPU,
that's essentially your answer, you'd need RAM to work at
DDR2-888 MHz speeds stably.
The question you then must ask is:
a) Can I buy DDR2-800MHz RAM and overclock it from 400 MHz stock
clock to 444 MHz actual clock to get my CPU to 4GHz? Answer: MAYBE,
but don't count on it. SOME RAM will OC that well, but a lot won't.
It's even more problematic if you have 4 DIMMS instead of just 2 DIMMS.
b) Should I just spend the money for DDR2-1000 memory (PC2-8000)?
Since 1000/2 = 500 MHz, it'd be guaranteed to work more than fast enough
to run your CPU at 444MHz * 9 = 4GHz. So no problems with it working,
but is the extra price worth it for 11% extra speed (444MHz vs 400 MHz ;
CPU 4000 MHz [at RAM = 444 MHz] vs 3600 MHz [at RAM = 400 MHz with
the cheaper 800 MHz DDR2 RAM]?
c) Should you just buy a different CPU model with a higher maximum multiplier
rate and save the money on the faster RAM, ie. get a CPU that can run
9.5 multiplier or 10.0 multiplier and then be able to get closer to 4GHz speed
and still use cheaper 400 MHz memory? Answer: your call; check what's
out there and the prices, and make the choice.
d) How sure are you your CPU will even be STABLE at 4GHz; not everyone
can overclock that high. A lot of people CAN do it, but a lot of others
don't get QUITE that high -- some get to 3.3GHz, 3.5GHz, or whatever.
You'll probably need a REALLY GOOD heatsink / fan to get to 4GHz, so
be prepared to spend enough on that to get a pretty top notch one and
learn to install it perfectly (with the right paste technique, etc.).
If in the end you're going to only possibly be running at 3.6 GHz due
to some limit in the CPU or whatever, you might as well have saved the
money on 1000 MHz RAM and run the 800 Mhz stuff instead.
As for brand? If you're buying 800 MHz RAM, any major reputable
brand and retailer should get you memory that will work OK for you.
Obviously it's not top of the line speed, so even some of the "value"
brands will be just fine. Even G.Skill, Ballistix, Corsair, etc. do make
some low performance / value memory that isn't necessarily technically
any better / faster than cheap no-name stuff.
For DDR2-800 PC2-6400 memory I'd look for 5-5-5-15 or better (lower
numbers in any / all positions) timings, and I'd look for 2 or 4
matched model DIMMs of 2GB/DIMM or 1GB/DIMM capacity.
I'd look for voltage of 1.8 (best), 1.9 (good), 2.0 (OK), or 2.1 (OK but
lower would be better) volt specified RAM voltage operation *AT*
800 MHz 5-5-5-15 speed.
One of the better models of Patriot (...-LLK / ..-ELK), G.SKILL, Ballistix,
GEIL, CRUCIAL, SuperTalent, etc. would be fine.
Look for a lifetime warranty on the RAM from the manufacturer, sometimes
the retailer sites aren't clear whether the MANUFACTURER warranty is
lifetime or not.
The T8UB2GC5 2GB 5-5-5-15 DDR2-800 DIMMs were like $35 a piece
at eWiz last time I looked (months ago, maybe they're similar now).
Here's a long list of 2GB capacity single DIMMs from Newegg as another
option.
http://www.newegg.com/Product/...94&bop=And&Order=PRICE
Check the Frys / Outpost site too for the Patriot and other decent models.
As for DDR2-1000 or DDR2-1066, that's relatively high performance memory,
so get the best deal you can on lifetime warranty memory that runs
at least as fast as 6-6-6-18, better 5-5-5-15, best 4-4-4-12 at
2.1V or less and the Max. rated MHz.
Newegg had some G.SKILLs in that category that tempted me a while back,
I'm sure Corsair / Ballistix / et. al. have other options.
Hot Deals forums on AT and FW are useful for finding the good deals.
The actual speed BENEFIT of 1066 MHz vs 1000 MHz vs 800 MHz memory
SPEED is not really significant, especially not for an Intel CPU like the
one you're getting. STRICTLY it's only even potentially worth buying
faster memory ONLY because you NEED the extra speed to run the CPU
MHz clock as fast as you need to to max out a given CPU's overclock.
The actual real world memory PERFORMANCE benefit due to the
faster MEMORY is in virtually all cases NOT worth cost of buying faster
memory than you need to; 800 MHz DDR2 is cheap-ish and is IDEAL
from a VALUE perspective.
Personally I bought 8GB of the SLOWER 800 MHz memory and I just
don't run my CPUs much faster than 3600MHz (the 400 MHz RAM
limits the CPU overclock) because in my book
MORE CHEAPER RAM is better than LESS but FASTER RAM / faster CPU.
Then again I got the quad core CPU which is an altogether different
strategy to make your CPU faster (more cores) rather than trying
to overclock a dual core CPU quite to the maximum.
But that depends on your priorities.
Good luck.