dual channel, with > 2 DIMMs

Caporegime
Joined
18 Oct 2002
Posts
32,654
Been out of hardware for a few years and now I'm a little confused.

I'm thinking of buying an i5 or i7 (1156) setup.

Default option is 2x2Gb ram. But I'm wondering if I will need more for future proofing.

I know 2x2 will run in dual channel mode, and dual channel mode will basically double bandwidth (like a HD RAID setup).

But what happens if you put 3X2 or 4x2GB dimms in?
with 3x2 dual channel do I get 2x2 in dual channel and 1x2 in single channel mode, or will all dimms run in single channel mode? with 4x2GB will I get 2 times a 2x2Gb dual channel setup?

What is the performance change from 2x2Gb going to 3x2Gb.


I mostly use Photoshop, lightroom, movies, DTP, and some gaming
 
Basically you can run dual channel with 2 x 1gig, 2 x 2gig, etc.

with 3 x 2 gig it will be in tri-channel with an x58 motherboard or sinlge channel with a P55 motherboard.

Really depends on which cpu and motherboard you are going for.?

imo if you go I5, 4gig would do.

and with I7, 6gig.
 
Was thinking of an i5 or i7 860 inthe 1156 chip, with a P55 motherboard. I don't really want to pay the extra for the 1336 motherboards.

I was thinking of just the i5 750, but realised I could spend 60 quid more and get the i7 860. This wont take tri-channel memory. I then wondered what the performance difference would be between the i5 with 8Gb of memory of the i7 and 4Gb of memory as they should cost the same. A half way solution is the i7 860 and 3x2Gb of memory but this wont run in a tri-channel setup.

I could get the I7 940 and 3x2Gb but this will require a £40 more expensive motherboard. Then it is all just a bit too expensive and I would prefer the basi i5 setup.


So I guess the real question is, what is the performance cost of not running in dual channel mode if 3x2Gb were used?
Also would it be possible to upgrade from a 2x2gb now and adding 2x2 or 2x4gb later?
 
Somewhere around 400-500 ideally, but I want to know my options if I spent a little more.

Given I have a few components, this doesn't include a monitor and I only need a mid end GFX card I was going for an i5 750 and 2x2Gb ram with cheapest mobo. £70 extra would buy an extra 4Gb of RAM or the i7 860. I was wondering which if either are really worth it.


This will mostly be for photoshop, lightroom, HD movie palyback and some video editing.
 
Just a tower, No OS, I have a case, and I excluded DVD although I might buy a blu-ray drive later outside of this budget.

Really it is: CPU + Memory + Mainboard + PSU + HSF (if needed) + mid-end GFX card + 500-1000GB HD.
 
Product Name Qty Price Line Total
CP-244-AM_60.jpg
AMD Phenom II X4 Quad Core 955 Black Edition 3.20GHz (Socket AM3) - Retail £149.98
(£130.42) £149.98
(£130.42)
GX-196-AS_60.jpg
Asus ATI Radeon HD 4770 512MB GDDR5 PCI-Express Graphics Card £79.34
(£68.99) £79.34
(£68.99)
CA-008-CS_60.jpg
Corsair TX 650W ATX SLi Compliant Power Supply (CMPSU-650TXUK) £72.99
(£63.47) £72.99
(£63.47)
MB-355-AS_60.jpg
Asus M4A785TD-V Evo AMD 785G (Socket AM3) PCI-Express DDR3 Motherboard £70.99
(£61.73) £70.99
(£61.73)
MY-109-OC_60.jpg
OCZ Platinum 4GB (2x2GB) DDR3 PC3-10666C7 1333MHz Dual Channel (OCZ3P13334GK) £65.99
(£57.38) £65.99
(£57.38)
HD-244-WD_60.jpg
Western Digital Caviar Black 640GB SATA-II 32MB Cache - OEM (WD6401AALS) £52.99
(£46.08) £52.99
(£46.08) Sub Total : £428.07 Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : FREE VAT is being charged at 15% VAT : £65.71 Total : £493.78
 
Last edited:
Thank you for the build spec.
I was thinking more along the lines of:

Intel Core i5 750 2.66Ghz (Lynnfield) (Socket LGA1156) - Retail £159.99

Gigabyte GA-P55M-UD2 Intel P55 (Socket 1156) DDR3 Motherboard £86.99

XFX ATI Radeon HD 4830 512MB GDDR3 - Retail £75.99

G.Skill Ripjaw 4GB (2x2GB) DDR3 PC3-12800C8 1600MHz Kit £67.99

Western Digital Caviar Green 500GB SATA-II 32MB Cache - OEM £39.99

Total: 442.44 Plus a £50-60 PSU
bringing it to £500


Now, I could pay the £67 to get the i7 860, or pay £67 to get an extra 4Gb of RAM.
I will also be buying in Switzerland so my prices are actually cheaper here.




Q) If I have 4x2Gb ram, will it run in dual channel mode??
 
Q) If I have 4x2Gb ram, will it run in dual channel mode??

Yes. In dual channel motherboards (like the P55 based 1156 socket ones), 2 or 4 sticks = dual channel. 1 or 3 = single channel.

In tri-channel motherboards (like the X58 based 1336 socket ones), 3 or 6 sticks = tri-channel. 2 or 4 = single channel.
 
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