Core i3/i5 Memory Performance: A step backwards?

Manufacturer: Intel

During our performance testing of Intel's latest Core i3 and i5 CPUs, we noticed a quirk about the memory performance of these Clarkdale CPUs: latency appears significantly higher than that of Bloomfield (LGA1366) and Lynnfield (LGA1156) CPUs. We firstly checked to see if the GMA HD integrated graphics was hogging memory access, but then decided to expand our investigation and crack out some older systems to so how memory bandwidth compared from old to new, and whether we have a genuine step forward in Intel's new CPUs.

So that we could just focus on memory performance, we opted to set the CPUs to use the same configurations in terms of clockspeed, with all of the CPUs running as close to 3.0GHz as possible. We also decided to test the Core i5 using both its integrated graphics and using a discrete graphics card; on the graphs below, 'IGP' indicates the system running with integrated graphics, and GPU with a graphics card.

Please also note that the internal hardware for the Core i3 is identical to that of the Core i5 tested here. The only difference is that the Core i3 does not include TurboBoost, which we've disabled anyway in our test.

Systems Tested

• Intel Core i5-650 (2.92GHz: 22 x 133, Clarkdale core), HyperThreading Enabled, Speedstep and TurboBoost Disabled
  
• 4GB DDR3 1,333MHz (dual channel) at 9-9-9-24-1T
  
  
• Intel Core i7-870 (2.926GHz: 22 x 133, Lynnfield core), HyperThreading Enabled, Speedstep and TurboBoost Disabled
  
• 4GB DDR3 1,333MHz (dual channel) at 9-9-9-24-1T
  
  
• Intel Core 2 Duo E8400 (2.997GHz: 9 x 333MHz), Speedstep Disabled
  
• 4GB DDR2 800MHz (dual channel) at 5-5-5-15-1T
  
  
• Intel Core 2 Duo E8400 (2.997GHz: 9 x 333MHz), Speedstep Disabled
  
• 4GB DDR3 1,333MHz (dual channel) at 9-9-9-24-1T
  
  
• AMD Phenom II X2 540 (3GHz: 15 x 200), Cool'n'Quiet Disabled
  
• 4GB DDR3 1,333MHz (dual channel) at 9-9-9-24-1T

Common Components

• Asus P7H57D Evo (Intel H57 0503 BIOS)
  
• MSI 785GM-E65 (AMD 785G 2.4 BIOS)
  
• DFI LANParty Jr. GF9400-T2RS (GeForce 9400 421 BIOS)
  
• Gigabyte GA-X48T-DQ6 (Intel X48 F5 BIOS)
  
• PC Power and Cooling Silencer 750W PSU
  
• Windows 7 Home Premium x64
  
• Intel 15.16.5.64.2021 WHQL
  
• GeForce Driver 196.21 WHQL
  
• ATI Radeon HD 5870
  
• Catalyst 9.12 WHQL

SiSoftware Sandra Lite 2010c (16.26)

Website: Sisoftware



Sisoft Sandra is a multi-threaded memory benchmark, so it does make use of the HyperThreading that both the Core i7-870 and Core i5-650 have, so it's perhaps not a complete shock to see the bandwidth of Intel's new architecture CPUs is almost twice that of the older LGA755 system. The Lynnfield i7-860 has four physical cores, but the same dual-channel memory controller as the Clarkdale i5-650, and comes out on top.

When we look at the latency though, Lynnfield is again the fastest thing on test and nearly 60 per cent faster than Clarkdale with IGP enabled. In fact, the Clarkdale i5-650 is actually slower than the old Core 2 systems in some circumstances (when both systems are running discrete GPUs).