h******u
发帖数: 155 | 1 1. Java memory leak不是真正techincal的memory leak（类似于 C/C++），并不是说
GC没有办法回收memory，而是很多时候programmer忘记及时release reference,以至于
不会再用的object还被 hold，所以导致GC无法 回收
2. GC工作原理是 reachability，一个object能不能被回收，完全决定于它是不是能从
一些roots 到达 （static fields, stack vars），如果没有办法到达，就是
unreachable了，就被回收掉了。但是如果原来 a.f reference在b, 你用完b，忘了把a
.f = null，b就一直reachable，一直没有办法被释放
3. String其实是一个很大的问题，通常会导致java 里面严重的memory问题。eclipse
里面的很多performance 问题实际上可以通过有效的strong 操作很好的避免。具体可
以看一下这些 tips
http://wiki.eclipse.org/Performance_Bloopers |
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a***n
发帖数: 1616 | 2 【 以下文字转载自 Java 讨论区 】
【 原文由 adven 所发表 】
用JDBC，最基本的数据库连接访问。开始还是好的。
过了一段时间后，就报错，说用完了shared memory，全被heap占用了。
网上说，要增加large pool size。
可是，我看了pool里的free memory，随着我程序的不断数据库访问，
它占用的pool memory是成递增的，最后就满了fail了。
所以，按这个趋势，无论我pool设多大，memory终究是要溢出的。。。
(我的large pool size已经是80M多了, 我也就做了一些简单的数据库访问而已)
我想是我java程序的问题。是不是要用shared sql? 让所有数据库访问用shared资源？
或者让已经做完的数据库操作把占用的heap dump掉？
这该到底怎么做啊。。。。？
谢了！ |
|
h*******r
发帖数: 207 | 3 其实这个问题已经在另外一个贴子里问了http://www.mitbbs.com/article_t/Database/31166033.html,为了让更多的大牛看到,所以另外开了这个.
我现在是使用database来做自己的分析,这些分析还没有商业的
应用,彻底是自己用. 我自己已经用MS SQL Server 2008建立了自己的数据库,但是传统
的数据库读写对于我的分析来说太慢了,所以现在正在看In Memory Database. 这些In
Memory Database的许可上面都写的很模糊.比如我曾经想用KDB,最后发现试用版有很多
限制,比如最多一次只能运行两小时,等等.
所以上来问问大牛们的建议:In Memory Database哪个比较好(速度快,有JDBC Driver,
免费版没有限制等等). 现在我这儿看到的In Memory Database有这几个:
Oracle的TimesTen,
MySQL的cluster，
VoltDB,
H2,
HSQLDB,
MonetDB,
SQLite
如果漏掉了重要的,大牛帮我补上吧. 大牛请指教!
谢谢! |
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o**f
发帖数: 76 | 4 我最近编了一些C#程序。有一些关于Memory的问题想请教。
The list class supports dynamic memory allocation. I
can get an element from a list with GetValue(). However,
if I modify the element I got via GetValue(), the real
element in the list is changed too. It seems that
GetValue returns the reference to that element (The C++
reference concept). Can anyone briefly describe how
memory space is managed by C#? For example, how C#
manage the memory space used by a list.
Thank you! |
|
t******8
发帖数: 2803 | 5 Hi. I've read a couple of recommended set-ups online and come up with this
question:
Why so many guys use a memory with a rated speed of 1600MHz instead of
1333MHz to use with i7-860 which only support up to 1333MHz? Is this an
overkill?
I'm looking into buy a kit of 2x2GB memories for P55-UD4P and i7-860. I
wonder which memory will perform better in the real world (I don't over
clock, but I'm willing to go to BIOS and adjust the memory timing):
1) 1600 MHz with 7-7-7-24
2) 1333 MHz with 7-7-7-2 |
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A*****O
发帖数: 394 | 6 日常使用，跑一些统计软件（SPSS & GraphPad Prism），一些小编程（R & python）
，做图（photoshop）。
劳烦大侠指点！怎么组合是够用而且划算的？
谢谢！
Processor
Intel Core i3-2350M Processor (3M Cache, 2.30GHz)
[add $105.00] Intel Core i5-2520M Processor (3M Cache, 2.50GHz)
[add $155.00] Intel Core i5-2540M Processor (3M Cache, 2.60GHz)
Total memory
4 GB PC3-10600 DDR3 SDRAM 1333MHz SODIMM Memory (1 DIMM)
6 GB PC3-10600 DDR3 SDRAM 1333MHz SODIMM Memory (2 DIMM)
8 GB PC3-10600 DDR3 SDRAM 1333MHz SODIMM Memory (2 DIMM) |
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F***Q
发帖数: 6599 | 7
if you have less than 16G memory, you still have the risk of exhausting your
memory if many chrome tabs are opened and left overnight. This happens
quite often for one of my laptops with 8G memory. I have to use OneTab
plugin to free up memory from time to time. |
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r*******w
发帖数: 121 | 8 anyone can recommend some articles/books which explains in deeper details how
the java memory management works? i saw from the web that memory leak is still
possible with java...and there are two types of memory leaks...but the article
does not elaborate...i strongly suspect i am having memory leaks...and
therefore would like to know more~
thanks~ |
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a***n
发帖数: 1616 | 9 用JDBC，最基本的数据库连接访问。开始还是好的。
过了一段时间后，就报错，说用完了shared memory，全被heap占用了。
网上说，要增加large pool size。
可是，我看了pool里的free memory，随着我程序的不断数据库访问，
它占用的pool memory是成递增的，最后就满了fail了。
所以，按这个趋势，无论我pool设多大，memory终究是要溢出的。。。
(我的large pool size已经是80M多了, 我也就做了一些简单的数据库访问而已)
我想是我java程序的问题。是不是要用shared sql? 让所有数据库访问用shared资源？
或者让已经做完的数据库操作把占用的heap dump掉？
这该到底怎么做啊。。。。？
谢了！ |
|
s*****p
发帖数: 5342 | 10 最近,我的JAVA APPLICATION(running on JBoss)总是out of memory. 我
知道可以加MEMORY to JVM.已经512MB了.我想还是我的PROGRAM有问题.
我不觉得IT需要那么多.问题可能还是出在MEMORY RELEASE,因为我的
CODE有一堆LOOP.怎么才能保证快速RELEASE MEMORY呢?
3x! |
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c*********t
发帖数: 2921 | 11 在Linux下，一个process运行的时候address space都会有stack section, data
section, test section, bss section,等等，以及由 malloc()所得到的 memory.
我的问题是，malloc()到底是从系统的什么地方得到的动态memory?是不是从所谓的
heap 得到的?
如果是这样，是不是 heap 就是整个系统共有的 memory pool,各个process可以从这里
动态的得到memory via malloc()?
谢谢！ |
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w*s
发帖数: 7227 | 12 you know each module (eth, serial, ddr memory, nand, ...) has different
physical memory map from cpu point of view,
we have 2 ddrs in 2 memory space, how's linux make it logically continuous ? |
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z***e
发帖数: 5393 | 13 right right, every OS has its memory pool or whatever for applicaiton to
allocate memory and then put it back.
If so, why do we have the experience that the windows becomes slow after
using it for a while. e.g. When you first start windows, the used memory is
around 400Mb, then you play WOW, use Visual Studio, open bunch of browsers,
and you terminate all the applications (using task manager). Supposingly the
memory usage should be back to the initial phase which is around 400Mb, but
in most cas |
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h**o
发帖数: 548 | 14 我想实现这个功能：
function1()
{
....
m1 = get the current physical memory;
....
m2 = get the current physical memory;
get the difference between m1 and m2;
}
也就是说我想算m1, m2 之间 程序用了多少memory.
请问如何得到当前的memory 哪？ |
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c**********e
发帖数: 2007 | 15 我知道老大们又在心里臭骂我了。可是面试题就这样问，我只好准备。Google了半天也
没弄明白。是不是IT业内人士不屑一顾的问题。
举例来说，下例是否memory overflow？
char* str=new char[5];
char* one="Is this a very stupid memory overflow?";
strcpy(str, one);
下面这个是不是memory overflow?
int a[3];
a[5]=10;
下面这个是不是memory overflow?
比如说 stack 的大小是 1 GB，结果我在 stack 上用的数组总共达到 1.2 GB。 |
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g*****g
发帖数: 34805 | 16 Here are my settings. But I have 16GB memory. In my opinion, you'll need at
least 4GB memory to avoid memory issue with Eclipse, it's a memory hog.
-vmargs
-XX:+UseParallelGC
-XX:PermSize=512M
-XX:MaxPermSize=1024M
-Xss2m
-Xms1024m
-Xmx2048m |
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t******e
发帖数: 8 | 17 I have a question about the memory in top command:
Memory: 2048M real, 31M free, 2813M swap in use, 2083M swap free.
Do I have the risk that the running program will terminate abnormally?
what's difference between real memory and swap memory ?
Thanks a lot ! |
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h**o
发帖数: 548 | 18 我在一台Solaris 机上运行一个程序,这台机器有49GRAM, 当此程序只用了4G RAM时中
断了并显示
out of memory.可这时候机器的free memory还很多有30G左右.这是怎么回事? 我并没
有限制这
个程序所能用的memory size. |
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n********e
发帖数: 92 | 19 【 以下文字转载自 Hardware 讨论区 】
发信人: northeagle (ll), 信区: Hardware
标 题: Memory limit adjustment help
发信站: BBS 未名空间站 (Sat Oct 8 03:30:45 2005), 转信
I am running some application on CYGWIN NT-5.1. The job was terminated and I
got the error information "Out of memory".
I am running on XP pro, 1GB SDRAM, 1GB virtual memory. The performance monitor
shows a the job used up to 200MB. Is there a memory limit set by CYGWIN? If
so, how to adjust it?
THX |
|
S******A
发帖数: 238 | 20 看了前面的一个帖子， 我也在看in search of memory, 不错。 我也很喜欢time,
love, memory. 尤其是喜欢讲到seymour benzer(是他吧） 半夜三更看果蝇从管子里爬
过去， 因为晚上安静。 在SFN会议上听过seymour benzer的讲座， 还有Dr. Lily Jan
抱着宝宝的照片， 很有意思。
都说到哪儿去了。
本来是想说说歧视和枪击的联系的。
在in search of memory里看到犹太人被逼蹲在马路上洗涮地上的字， 周围站着其他的
维也纳人看。这也够歧视的啦。从几千年前到不是很久以前，犹太人没有自己的国家，
一直受到其他民族的歧视， 可是为什么他们占诺贝尔奖中的那么多（据说是50%? 不是
很确定）。
刚刚看到in search of memory 里的一段话，对我之前一直的疑问有了一点解释。 我
抄一下吧
My parents shared the values of most other Viennese parents: they wanted
their children to achieve something |
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r**u
发帖数: 42 | 21 Calculate or check how many memory you need from workspace window.
You need a “continuous” block of memory for a matrix.
1. make the biggest matrix smaller
2. assign memory for the biggest matrix at beginning of running
Please refer Memory Management Guide
http://www.mathworks.com/support/tech-notes/1100/1106.html |
|
m*****t
发帖数: 3477 | 22 【 以下文字转载自 JobHunting 讨论区 】
发信人: weiqing (weiqing), 信区: JobHunting
标 题: 招人，有5年工作经验的做memory的工程师
发信站: BBS 未名空间站 (Tue Jul 20 15:20:32 2010, 美东)
发信人: weiqing (weiqing), 信区: SanDiego
标 题: 招人，有5年工作经验的做memory的工程师
发信站: BBS 未名空间站 (Tue Jul 20 15:15:43 2010, 美东)
现在qualcomm@san diego正在hire一个有5年工作经验的做memory的工程师，熟悉compi
ler和costum memory design。很遗憾，新毕业的不要。
有意者跟我联系吧。 |
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a*****x
发帖数: 12 | 23 如果Intel是做memory reliability, SanDisk是做memory device design，哪个工作前
景比较好？
一个是大公司，但不是核心部门，内容也比较窄。一个是主流做memory的核心部门。要
怎么比较呢？
谢谢！ |
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a********a
发帖数: 346 | 24 Thanks goldmember,
The memory in my computer is only 1G. The problem is now I only want to get
120*8 matrix to test the program, but it stopped only give an output 66*8.
I tried to use library(bigmemory), it does not work.
If I use memory.size(max = TRUE), the memory only have a size 488.31
memory.size(max = TRUE)
>488.31
Do you have any other idea? |
|
g********r
发帖数: 8017 | 25 If it is windows, you may need to do memory.limit() to make more memory
available to R. Otherwise more
memory doesn't help at all.
I guess the process you use to generate the estimates uses large matrices.
Otherwise it doesn't make sense
for a 24000x8 matrix to occupy so much memory. |
|
o****o
发帖数: 8077 | 26 if your memory is big enough, such as in your case, you can load the whole
data into memory and all SAS operations can be done completely in memory, no
disk I/O involved except initial load
for example, check "sasfile" statement
some procedures can specify memory size, for instance: PROC SORT ....
SORTSIZE=4G....
check its online documentation at support.sas.com
of
manages
dataset |
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l**********n
发帖数: 303 | 27 Hello, I am having trouble with unsufficient memory in SAS, does anyone know
how to allocate more memory in SAS? Thanks a lot!
Error: Unable to allocate sufficient memory: a request for 360113K bytes exceeded the 786430K available. Note that the deficit amount may not be the amount of memory needed for a successful run, since it does not reflect subsequent allocations by this or other processes. |
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t****r
发帖数: 592 | 28 在Memory混过一段时间了,做为平民,一度想离开却又有牵挂.
不想星星和河马几乎同时辞去Memory版主/副职位,只有傻张同学一人独撑, 不希望看到
昔日热爱的版块冷落下来, 也不希望星星和河马牵挂的jhq整理一直成为牵挂, 希望能
尽自己一些力为大家做些事:
一,保持本版的休闲性和娱乐性。Memory是个让大家在学习工作之余放松的场所, 不带
某些目的指向性, 言论自由. 保持Memory版的原则(鼓励和保护原创; 保护MM):)
二,整理好jhq.
期间如有合适的人有申请版主意向,我当马上退出. |
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w*******y
发帖数: 60932 | 33 Memory foam is renown for its effective qualities of pressure reduction and
support. This is a very luxurious version of Tempurpedic's Medium Neck
Pillow that retails for $99. The super soft, velour cover is removable and
can be laundered. Unlike other cut memory foam pillows, this is molded and
has a soft, doughy feel. The memory foam is naturally antimicrobial and dust
mite resistant. It sleeps cool and adapts to your body's temperature.
Includes: One 20" x 12" x 4" Contour Memory Foam Pillow |
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w*******y
发帖数: 60932 | 34 Corsair 4 GB DDR3 Laptop Memory Kit CMSO4GX3M2A1333C9 for $76.46 shipped on
Amazon
4GB (2 X 2GB) DDR3 Laptop Memory Kit - 1333MHz Unbuffered CL 9 SODIMM Memory
9-9-9-24 1.5V
Link:
http://www.amazon.com/Corsair-DDR3-Laptop-Memory-CMSO4GX3M2A1333C9/dp/B002YUBVES/
It has been posted at higher price before. I think that it's good price as
other 4GB DDR3 SODIMM kits usually go for around $100. It seems that this
kit works fine for Macbook Pro according to some posts.
|
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w*******y
发帖数: 60932 | 35 J&R has these Link:
http://www.jr.com/crucial/pe/CRT_4GK2564BA13/
for 74.99 after $10 instant rebate. Wonder how good these modules are.
240-pin DIMM / DDR3 PC3-10600 / CL=9 / Unbuffered / NON-ECC / DDR3-1333 / 1.
5V / 256Meg x 64
Crucial 240-pin DIMMs are used in DDR3 Memory for Desktop computers. DDR3 is
the latest generation of memory with an improved Architecture that allows
it to transmit Data more quickly. A dual inline memory module (DIMM)
consists of a number of memory components (usuall |
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w*******y
发帖数: 60932 | 36 mwave has PQI 8GB SDHC Class10 150X flash memory card:
http://www.mwave.com/mwave/skusearch_v3.asp?scriteria=BA39525&pagetitle=PQI 8GB SDHC Class10 150X flash memory card
for $11.99 + FS for mclub members (free to join)
If you haven't used your $10 coupon you can get this SD card for $1.99 Ac
and if you use E-Billme you will get additional 5% off)
Description:
PQI 8GB Class10 150X Flash Memory Card
PQI SDHC Class10 150X flash memory card uses FAT32 file format and is
available from 8GB in capa... 阅读全帖 |
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w*******y
发帖数: 60932 | 37 Link:
http://www.bestbuy.com/site/Toshiba - Satellite Laptop / Intel® Celeron® Processor / 15.6" Display / 2GB Memory / 250GB Hard Drive - Black/1261751.p?id=1218244146938&skuId=1261751&st=1261751, 1380742, 1450344, 1502152_&cp=1&lp=1
What's Included
Toshiba Satellite Laptop / IntelCeleronProcessor / 15.6" Display / 2GB
Memory / 250GB Hard Drive
6-cell lithium-ion battery
65W AC adapter
Software: Microsoft Silverlight, Microsoft Live Essentials; Adobe Acrobat
Reader
Owner's manual
Prod... 阅读全帖 |
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w*******y
发帖数: 60932 | 38 Link:
http://www.bestbuy.com/site/Toshiba - Satellite Laptop / Intel® Celeron® Processor / 15.6" Display / 2GB Memory / 250GB Hard Drive - Black/1261751.p?id=1218244146938&skuId=1261751
What's Included
Toshiba Satellite Laptop / IntelCeleronProcessor / 15.6" Display / 2GB
Memory / 250GB Hard Drive
6-cell lithium-ion battery
65W AC adapter
Software: Microsoft Silverlight, Microsoft Live Essentials; Adobe Acrobat
Reader
Owner's manual
Product Features
IntelCeleronprocessor 900
Features a... 阅读全帖 |
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w*******y
发帖数: 60932 | 39 BUNDLE #1 - SAVE $245 OFF our regular price OUR PRICE
IntelCore i7 875K Unlocked 2.93GHz Boxed Processor $299.99
INSTANT IN-STORE ONLY SAVINGS -$50.00
ASUS P7P55D-E LX LGA 1156 P55 ATX Intel Motherboard $129.99
$10 mfr. mail-in rebate -$10.00
4GB DDR3-1333 Dual-Channel Memory Kit (2 x 2GB Memory Modules) $49.99
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BUNDLE #2 - SAVE $190 OFF our regular price OUR PRICE
IntelCore i7 875K Unlocked 2.93GHz Boxed Processor $299.99
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w*******y
发帖数: 60932 | 40 Super Talent Notebook Memory: 4GB (1x4GB) DDR3-1333 SO-DIMM $34 or Two Sets
$67, 4GB (1x4GB) DDR3 1333 Micron Chip $36 or Two Sets $70, 4GB (1x4GB) DDR3
-1066 Micron Chip $38 or Two
Ewiz has 4GB (1x4GB) Super Talent DDR3-1333 SO-DIMM Notebook Memory for $37.
99 - 10% off with code HIBERNATE10 = $32.29. Shipping is ~$2. Thanks
justinkw1
If you order two sets, total is $64.58 + $2.18 shipping = $68.
Ewiz also has 4GB (1x4GB) Super Talent DDR3-1333 SO-DIMM Micron Chip
Notebook Memory for $37.99 - ... 阅读全帖 |
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w*******y
发帖数: 60932 | 43 http://www.staples.com/Toshiba-Satellite-L675D-S7107-17.3-Lapto
Processor AMD Phenom II Dual-Core Mobile Processor N66
Memory (RAM) 4GB
Memory Type DDR3
Memory Expandable to 8GB
Hard Drive Size 500GB
Hard Drive Type SATA
Optical Drive Blu-Ray Disc BD-ROM and DVD SuperMulti drive with Labelflash
Display Size 17.3"
Display Type TruBrite TFT display
Operating System Genuine Windows 7 Home Premium 64-bit
Battery Type 6 cell/48Wh Lithium Ion
Network Card Wi-Fi Wireless networking (802.11b/g/n)
Video ... 阅读全帖 |
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w*******y
发帖数: 60932 | 44 Memory Foam Pillows at Kohl's $15.74 with Kohl's Charge Card and coupon
codes.
Home Classics Memory Foam Contour Pillow:
http://www.kohls.com/kohlsStore/landingpages/memoryfoam/pillows Classics Memory Foam Contour Pillow.jsp
To get the price, use the following two coupon codes.
30% Off SHOPNSAVE30
Free SH FREE4MVC
I've been looking for a great deal on Memory Foam pillows, and coming from
Kohl's, if I don't like them, I can take them back to a B&M store without
being hassled.
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w*******y
发帖数: 60932 | 45 Link:
http://www.amazon.com/o/ASIN/B0040JHI4S
Technical Details
10.2" Digital photo frame, 1024x600 High resolution, 16:9 aspect ratio
High brightness 400 cd/m2 (typ.) & 400:1 (typ.) contrast ratio, 128MB
Internal Memory
Calendar & clock features, Random (Shuffle) slide show
Auto on/off feature, USB host/slave, Remote control included
Brightness and contrast adjustment, Support SD/MS/MS Pro/SDHC/MMC
Product Description
The high 1024x600 resolution LCD screen provides brilliant picture quality.
I... 阅读全帖 |
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w*******y
发帖数: 60932 | 46 Toshiba - Satellite Laptop / IntelCore i3 Processor (Sandy Bridge) / 15.6"
Display / 3GB Memory / 320GB Hard Drive - Black
Link:
http://www.bestbuy.com/site/Toshiba - Satellite Laptop / Intel® Core™ i3 Processor / 15.6" Display / 3GB Memory / 320GB Hard Drive - Black/2833077.p?skuId=2833077&id=1218354609804
IntelCore i3-2310M processor
Features a 3MB cache and 2.1GHz processor speed.
IntelCore i3 processor
Features smart 4-way processing performance for HD quality computing. Intel
HD g... 阅读全帖 |
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w*******y
发帖数: 60932 | 48 AVEXIR AVD3U16000902G-2SW Standard 4GB ( 2GB x 2 ) 240-pin DDR3 1600mhz non-
ECC desktop memory module $19.99 f/s AC
$10 OFF with Coupon Code "AVEXIR10" (Expires 7/22/2011)
Link:
http://www.mwave.com/mwave/SKUSearch.asp?px=DS&scriteria=BA4204
Description:
Backed with Avexir IC Sorting Technology (AIST), it unleashes the
performance within! Pre-screened only the best memory IC and components for
Avexir Standard Series, Standard series delivers rock-solid stability and
highest compatibility at... 阅读全帖 |
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