Dell Precision M6700 Owner's Review

Tested with SiSoft Sandra 2012:

Float Memory Bandwidth:

1333 - 17.310GB/s Hynix 9-9-9 @ 1333
1600 - 19.943GB/s Hynix 11-11-11 @ 1600
1866 - 23.914GB/s Kingston 11-11-11 @ 1866

Integer Memory Bandwidth:

1333 - 17.319GB/s Hynix 9-9-9 @ 1333
1600 - 19.929GB/s Hynix 11-11-11 @ 1600
1866 - 23.898GB/s Kingston 11-11-11 @ 1866

All running 4 way interleaving.

 

Yup. My current project is highly memory bound ... a flaw I'm trying to fix. Even so, I opted for 32GB of 1600.

 

If I can see the overall system responsiveness boost in general use when moving from 1600 to 1866 - it's not negligible. One thing to note though, I was running an OC'ed 2960XM @4.5GHz, maybe the faster ram reduced a mild bottleneck? Still, even without doing anything RAM heavy I can notice the difference with my own eyes.

 

There is a lot of information out there about the Desktop versions of Ivy Bridge chips and chipsets. We know the Desktop versions will allow DDR Frequency overrides up to 2667 even when the stated max speed is 1600.

The numbers I am seeing are very close to what Tom's Hardware got when they tested the i7-3770K. Ivy Bridge Memory Scaling : Intel Core i7-3770K Review: A Small Step Up For Ivy Bridge

I am saying this VERY cautiously, but I think the Ivy Bridge chipset in the M6700 is allowing a DDR speed override to 1866.

The numbers certainly show a big jump there. I am currently trying to find some CAS 9 DDR3 1600 ram to test. Since the 1866 ram runs at CAS 9 @ 1600, this would rule out any gains from a lower latency.

 

Thanks. I'm going to see if Intel can provide any answers about this. Can you confirm via CPU-Z that the 1866 memory is in fact running at full speed?

 

As far as I was aware, everything on mobile i7 is dual-channel only...?

 

HWInfo64:


CPU-Z


Enth and Extreme Memory Profiles


Yes, the 3920XM DOES support DDR overclocking


And it is currently overclocking from 1600 to 1866

 

Interesting! Thanks for taking the time to figure this out.

Any idea what the maximum supported memory speed would be?

 

Max speed is defined by the memory profiles stored in the RAM itself. The system reads these profiles and sets the speed accordingly.

Normal supported speed is the Enthusiast / Certified profile. This is what the Memory will support in all systems. On this the speed is 1600 9-9-9

If a machine support the Extreme profile, it will use it. The Extreme profile in this memory is 1866 11-11-11.

Going to try and paste in the profiles below...

Enthusiast / Certified Profile [Enabled]
Module VDD Voltage Level: 1.40 V
Memory Controller Voltage Level: 1.20 V
CAS# Latencies Supported: 7, 8, 9
Minimum SDRAM Cycle Time (tCKmin): 1.250 ns (800.0 MHz)
Minimum CAS Latency Time (tAAmin): 11.250 ns
Minimum RAS# to CAS# Delay Time (tRCDmin): 11.250 ns
Minimum Row Precharge Delay Time (tRPmin): 11.250 ns
Minimum Active to Precharge Delay Time (tRASmin): 35.000 ns
Minimum CAS Write Latency Time (tCWLmin): 11.250 ns
Minimum Write Recovery Time (tWRmin): 15.000 ns
Minimum Active to Active/Refresh Delay Time (tRCmin): 46.250 ns
Maximum tREFI Time (Average Periodic Refresh Interval): 7.875 us
Minimum Refresh Recovery Delay Time (tRFCmin): 160.000 ns
Minimum Internal Read to Precharge Command Delay Time (tRTPmin): 7.500 ns
Minimum Row Active to Row Active Delay Time (tRRDmin): 6.000 ns
Minimum Four Activate Window Delay Time (tFAWmin): 30.0 ns
Minimum Internal Write to Read Command Delay Time (tWTRmin): 7.500 ns
Supported Module Timing at 800.0 MHz: 9-9-9-28
Read to Write CMD Turn-around Time Optimization: No adjustment
Write to Read CMD Turn-around Time Optimization: No adjustment
Back 2 Back CMD Turn-around Time Optimization: No adjustment
System Command Rate Mode: Default

Extreme Profile [Enabled]
Module VDD Voltage Level: 1.40 V
Memory Controller Voltage Level: 1.30 V
CAS# Latencies Supported: 9, 10, 11
Minimum SDRAM Cycle Time (tCKmin): 1.071 ns (933.3 MHz)
Minimum CAS Latency Time (tAAmin): 11.786 ns
Minimum RAS# to CAS# Delay Time (tRCDmin): 11.786 ns
Minimum Row Precharge Delay Time (tRPmin): 11.786 ns
Minimum Active to Precharge Delay Time (tRASmin): 34.000 ns
Minimum CAS Write Latency Time (tCWLmin): 9.643 ns
Minimum Write Recovery Time (tWRmin): 15.000 ns
Minimum Active to Active/Refresh Delay Time (tRCmin): 45.786 ns
Maximum tREFI Time (Average Periodic Refresh Interval): 7.786 us
Minimum Refresh Recovery Delay Time (tRFCmin): 160.000 ns
Minimum Internal Read to Precharge Command Delay Time (tRTPmin): 9.643 ns
Minimum Row Active to Row Active Delay Time (tRRDmin): 6.000 ns
Minimum Four Activate Window Delay Time (tFAWmin): 35.0 ns
Minimum Internal Write to Read Command Delay Time (tWTRmin): 7.500 ns
Supported Module Timing at 933.3 MHz: 11-11-11-32
Read to Write CMD Turn-around Time Optimization: No adjustment
Write to Read CMD Turn-around Time Optimization: No adjustment
Back 2 Back CMD Turn-around Time Optimization: No adjustment
System Command Rate Mode: Default

 

The M4700 & the M6700 both run the 1866MHz at speed. Dell, working with Intel, certify the systems to run at this higher speed.

Tks
Dell-Mano_G