Overclock.net › Forums › General Hardware › General Processor Discussions › if same arch and clocks, edram or high L3?
New Posts  All Forums:Forum Nav:

if same arch and clocks, edram or high L3?

post #1 of 4
Thread Starter 
http://ark.intel.com/products/93791/Intel-Xeon-Processor-E7-8893-v4-60M-Cache-3_20-GHz

http://ark.intel.com/products/88040/Intel-Core-i7-5775C-Processor-6M-Cache-up-to-3_70-GHz
Assuming they worked on the same board and at equal cost

If both were locked to 3300mhz, would the 60MB L3 beat the 128MB L4? Both quad cores with HT and are the same architecture. Slower but doubled the cache or faster but half the cache


just curiosity
Edited by czin125 - 8/5/16 at 7:59am
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
E6850 evga 680i a1 XFX 5770 11.7_Drivers_Aug15-2011) 4GB DDR2 800 
Hard DriveOSMonitorPower
320 GB SATA Windows 7 Ultimate x86 22inch display 1680x1050 750W Silverstone 
Case
antec 900 
  hide details  
Reply
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
E6850 evga 680i a1 XFX 5770 11.7_Drivers_Aug15-2011) 4GB DDR2 800 
Hard DriveOSMonitorPower
320 GB SATA Windows 7 Ultimate x86 22inch display 1680x1050 750W Silverstone 
Case
antec 900 
  hide details  
Reply
post #2 of 4

eDRAM is video RAM, not general use cache.

The girlfriend.
(15 items)
 
The Mistress
(13 items)
 
Media Server
(11 items)
 
CPUMotherboardGraphicsRAM
A8-6410 Lenovo Lancer 4B2 K16.3 R5 128 Shaders/M230 Hynix 8GB DDR3 1600 
Hard DriveHard DriveOSMonitor
Samsung 840 120 GB SSD Seagate Momentus 1TB 5400rmp Win 8.1 CMN1487 TN LED 14" 1366*768 
KeyboardPowerMouseMouse Pad
Lenovo AccuType 2900mAh/41Wh Elan Trackpad/Logitech M90 Super Flower 
Audio
AMD Avalon(Connexant) 
  hide details  
Reply
The girlfriend.
(15 items)
 
The Mistress
(13 items)
 
Media Server
(11 items)
 
CPUMotherboardGraphicsRAM
A8-6410 Lenovo Lancer 4B2 K16.3 R5 128 Shaders/M230 Hynix 8GB DDR3 1600 
Hard DriveHard DriveOSMonitor
Samsung 840 120 GB SSD Seagate Momentus 1TB 5400rmp Win 8.1 CMN1487 TN LED 14" 1366*768 
KeyboardPowerMouseMouse Pad
Lenovo AccuType 2900mAh/41Wh Elan Trackpad/Logitech M90 Super Flower 
Audio
AMD Avalon(Connexant) 
  hide details  
Reply
post #3 of 4
Quote:
Originally Posted by Liranan View Post

eDRAM is video RAM, not general use cache.

eDRAM is L4, accessed by both the CPU and GPU. It's nothing more than a tier in the memory hierarchy between RAM and L3. Designed with the integrated graphics in mind, sure, but it still benefits the CPU. I imagine it helps with the Xeon E3-1200 v4 series to some degree as, say, web or file servers. More L3 would be expensive, but a DRAM die isn't too much extra.


Assuming all else is equal, it really depends. For smaller files that can fit within 60MiB of memory, the Xeon will win since its L3 ought to be faster. For files between 60MiB and 128MiB, the i7 should win, as it has access to L4. For files beyond that, it should be about equal (if we use similar memory configurations of course).

Or so you'd think. In reality, it's never that simple. Even adding L3 isn't a sure fire way to increase performance thanks to how cache works. A friend explained it to me (and 90% of it went over my head) but it has to do with how cache is accessed and I think "predictions" of where some data might be.

Techreport did some synthetic benchmarks as well and includes some interesting results. Skylake and Haswell have similar latencies, but Broadwell and its L4 show a significant gap where its L4 would be most effective, compensating for its reduced L3 (6MiB rather than 8MiB). Keep in mind that it's a logarithmic scale, so the L4 is accessed in about half the cycles compared to Skylake and Haswell needing to access system memory, probably because it's on the CPU package rather than through the motherboard. If you look at the very first graph, there's a very tiny gap where the 5775C edges out vs the 5960X. But compared to a processor with three times the L3, I'd assume that even the L4 couldn't help it and the E7 would win hands down.

Well, except price. $7000 for a quad-core is a bit much, don't you think? wink.gif

EDIT: Also, for some history and explanation of cache, read this. It goes into cache hits and misses as well as associativity.

EDIT 2: Neat, part 2 here. The die shots really emphasize just how much space is dedicated to cache on die and why L3 is so expensive. My Xeon (Haswell GT2, same as the 4790K) contains exactly 9 699 328 bytes of SRAM acting as cache - the vast majority being L3 - made up of 465 567 744 transistors (~465 million). The die itself contains 1.4 billion in total, meaning about a third of the transistors on this CPU are dedicated to cache. And given that a significant part of the die goes to the integrated graphics, I'd guesstimate that about half of the CPU portion of the die is cache.
Edited by CynicalUnicorn - 8/6/16 at 9:24pm
Triumvirate
(20 items)
 
Osmium
(8 items)
 
For Sale: [FS] Z97 system: Xeon and RAM
$160 (USD) or best offer
CPUMotherboardGraphicsGraphics
i7-5775C ASUS Sabertooth Z97 Mark 2 Sapphire RX 480 (reference) MSI Low-Profile 750Ti 
RAMHard DriveHard DriveHard Drive
Corsair Dominator Platinum - 2x8GB Crucial M500 - 960GB Samsung 840 - 250GB WD Scorpio Blue - 1TB 
Hard DriveCoolingCoolingOS
ADATA SP900 - 64GB Scythe BIG Shuriken 2 Rev. B PNY Quadro 600 blower Windows 10 
MonitorMonitorMonitorKeyboard
ASUS VE247H - 1080p Gateway FPD1960 - 1280x1024 Samsung S20D300 - 900p, portrait Rosewill RK9000I - Cherry MX Blue 
PowerCaseMouseOther
Rosewill HIVE 650W Riotoro CR1080 SteelSeries Rival 100 CyberPower 1500PFCLCD 
CPUMotherboardRAMHard Drive
AMD A10-7870K ASRock FM2A88X-ITX+ G.Skill Ripjaws X - 2x4GB @ 2400MT/s Samsung 840 120GB 
CoolingOSPowerCase
Evercool EC-HPS-810CP Windows 7 Pro 64-bit PicoPSU-120-WI-25 Mini-Box M350 
  hide details  
Reply
Triumvirate
(20 items)
 
Osmium
(8 items)
 
For Sale: [FS] Z97 system: Xeon and RAM
$160 (USD) or best offer
CPUMotherboardGraphicsGraphics
i7-5775C ASUS Sabertooth Z97 Mark 2 Sapphire RX 480 (reference) MSI Low-Profile 750Ti 
RAMHard DriveHard DriveHard Drive
Corsair Dominator Platinum - 2x8GB Crucial M500 - 960GB Samsung 840 - 250GB WD Scorpio Blue - 1TB 
Hard DriveCoolingCoolingOS
ADATA SP900 - 64GB Scythe BIG Shuriken 2 Rev. B PNY Quadro 600 blower Windows 10 
MonitorMonitorMonitorKeyboard
ASUS VE247H - 1080p Gateway FPD1960 - 1280x1024 Samsung S20D300 - 900p, portrait Rosewill RK9000I - Cherry MX Blue 
PowerCaseMouseOther
Rosewill HIVE 650W Riotoro CR1080 SteelSeries Rival 100 CyberPower 1500PFCLCD 
CPUMotherboardRAMHard Drive
AMD A10-7870K ASRock FM2A88X-ITX+ G.Skill Ripjaws X - 2x4GB @ 2400MT/s Samsung 840 120GB 
CoolingOSPowerCase
Evercool EC-HPS-810CP Windows 7 Pro 64-bit PicoPSU-120-WI-25 Mini-Box M350 
  hide details  
Reply
post #4 of 4
Quote:
Originally Posted by CynicalUnicorn View Post
 
Quote:
Originally Posted by Liranan View Post

eDRAM is video RAM, not general use cache.

eDRAM is L4, accessed by both the CPU and GPU. It's nothing more than a tier in the memory hierarchy between RAM and L3. Designed with the integrated graphics in mind, sure, but it still benefits the CPU. I imagine it helps with the Xeon E3-1200 v4 series to some degree as, say, web or file servers. More L3 would be expensive, but a DRAM die isn't too much extra.


Assuming all else is equal, it really depends. For smaller files that can fit within 60MiB of memory, the Xeon will win since its L3 ought to be faster. For files between 60MiB and 128MiB, the i7 should win, as it has access to L4. For files beyond that, it should be about equal (if we use similar memory configurations of course).

Or so you'd think. In reality, it's never that simple. Even adding L3 isn't a sure fire way to increase performance thanks to how cache works. A friend explained it to me (and 90% of it went over my head) but it has to do with how cache is accessed and I think "predictions" of where some data might be.

Techreport did some synthetic benchmarks as well and includes some interesting results. Skylake and Haswell have similar latencies, but Broadwell and its L4 show a significant gap where its L4 would be most effective, compensating for its reduced L3 (6MiB rather than 8MiB). Keep in mind that it's a logarithmic scale, so the L4 is accessed in about half the cycles compared to Skylake and Haswell needing to access system memory, probably because it's on the CPU package rather than through the motherboard. If you look at the very first graph, there's a very tiny gap where the 5775C edges out vs the 5960X. But compared to a processor with three times the L3, I'd assume that even the L4 couldn't help it and the E7 would win hands down.

Well, except price. $7000 for a quad-core is a bit much, don't you think? wink.gif

EDIT: Also, for some history and explanation of cache, read this. It goes into cache hits and misses as well as associativity.

EDIT 2: Neat, part 2 here. The die shots really emphasize just how much space is dedicated to cache on die and why L3 is so expensive. My Xeon (Haswell GT2, same as the 4790K) contains exactly 9 699 328 bytes of SRAM acting as cache - the vast majority being L3 - made up of 465 567 744 transistors (~465 million). The die itself contains 1.4 billion in total, meaning about a third of the transistors on this CPU are dedicated to cache. And given that a significant part of the die goes to the integrated graphics, I'd guesstimate that about half of the CPU portion of the die is cache.

Thank you very much for correcting me. Too bad can't rep you, dear mod.

The girlfriend.
(15 items)
 
The Mistress
(13 items)
 
Media Server
(11 items)
 
CPUMotherboardGraphicsRAM
A8-6410 Lenovo Lancer 4B2 K16.3 R5 128 Shaders/M230 Hynix 8GB DDR3 1600 
Hard DriveHard DriveOSMonitor
Samsung 840 120 GB SSD Seagate Momentus 1TB 5400rmp Win 8.1 CMN1487 TN LED 14" 1366*768 
KeyboardPowerMouseMouse Pad
Lenovo AccuType 2900mAh/41Wh Elan Trackpad/Logitech M90 Super Flower 
Audio
AMD Avalon(Connexant) 
  hide details  
Reply
The girlfriend.
(15 items)
 
The Mistress
(13 items)
 
Media Server
(11 items)
 
CPUMotherboardGraphicsRAM
A8-6410 Lenovo Lancer 4B2 K16.3 R5 128 Shaders/M230 Hynix 8GB DDR3 1600 
Hard DriveHard DriveOSMonitor
Samsung 840 120 GB SSD Seagate Momentus 1TB 5400rmp Win 8.1 CMN1487 TN LED 14" 1366*768 
KeyboardPowerMouseMouse Pad
Lenovo AccuType 2900mAh/41Wh Elan Trackpad/Logitech M90 Super Flower 
Audio
AMD Avalon(Connexant) 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: General Processor Discussions
Overclock.net › Forums › General Hardware › General Processor Discussions › if same arch and clocks, edram or high L3?