An intelligence gathering system widely used by the Army in Afghanistan to detect roadside bombs and predict insurgent activity has severe limitations and is "not suitable," according to a memo from the Army's senior equipment tester to the Army's chief of staff, Gen. Raymond Odierno.

The e-mail memo was sent to Odierno on August 1, and comes as the system -- known as the Distributed Common Ground System (DCGS) -- is in the middle of Army and congressional investigations.

The inquiries surrounds a newly developed software system called Palantir, which -- according to U.S troops and commanders who have used it -- is more effective in helping troops in Afghanistan track and predict the location of deadly roadside bombs than the existing DCGS.

The memo to Odierno, written by the head of the Army's test and evaluation command -- Gen. Genaro J. Dellarocco -- hammers the DCGS system for its "poor reliability" and "significant limitations," during operational testing and evaluation earlier this year.

The memo covers an evaluation of the DCGS during May and June of this year, according to the document, which was first reported in the Washington Times.

It is not clear what prompted the evaluation, which came during a time when the DCGS was still being heavily criticized by troops in the field as inferior for discovering roadside bombs and after requests to field the software were denied by Army civilians at the Pentagon.

While the language of the memo was technical in nature, it describes the DGCS software during testing of its overall systems as having limited effectiveness and "poor reliability" as exemplified by "server failures that resulted in reboots/restarts every 5.5 hours of test."

The memo also said that during high usage the system suffers decreased reliability and its software characteristics "negatively impacted operator confidence and increased their frustration."

During tests to see how the system can protect itself during cyberattacks, the evaluation was again poor, saying evaluators were able to, "identify and exploit several vulnerabilities," and recommended that a "tech bulletin" be distributed to troops in Afghanistan using the system to warn them of the hacking vulnerability.

In a response to CNN inquiries about the memo, Army spokesman George Wright said, "The report provides an initial review of DCGS software, which identified specific limitations in its performance. Many of these limitations were already identified by the Army and software updates have been implemented to address the concerns."

"Military software applications and tools today are similar to our smartphones -- applications are constantly updated to meet user needs. The version of DCGS-A identified in this test is undergoing improvement in a constantly evolving process," Wright said.

At the end of the report, Gen. Dellarocco said that a different testing office -- one run by Pentagon civilians -- will give a rating that is, "mostly not effective, not suitable and not survivable."

"The Army relies on the testing community to provide evaluations and assessments of Army equipment, and we use their feedback to make necessary modifications to ensure we are providing the force with a capability that meets Army requirements and soldiers' needs," Wright said.

"The Army is currently working to further improve DCGS-A capabilities as we receive feedback from soldiers and units in combat," Wright continued.

"The Army's approach, which focuses on effective capabilities delivered to soldiers -- not specific commercial products -- is designed to field the latest technologies as we continuously strive for improvement."

The DCGS system came under fire last month when Rep. Duncan Hunter, R-California, cried foul after seeing U.S. Army documents that showed commanders in Afghanistan had been asking for the competitor system, called Palantir, but were repeatedly denied access to it by Army civilians in the Pentagon who insisted the soldiers keep using an inferior DCGS.

The Army has spent over $2.3 billion in procurement and research and development to fund the DCGS, while the Palantir system requested by U.S. troops is about $2 million, according to congressional staff familiar with the programs.

"I just want to make people realize we are still at war on the ground in Afghanistan and ground combat commanders are asking for gear that they're not getting," Hunter told CNN Tuesday.

"They're not getting it because the bureaucracy and the Pentagon civilians have stopped them for their own personal gain and that's what upsets me in this case," he said.

Reports showed that the newer Palantir system was better at detecting roadside bombs than DCGS, and other services, like the Marines and Air Force, had full access to Palantir while only a few Army units were allowed to use the system.

Additionally, documents showed that Army test and evaluation command, the same group that wrote the August 1 memo, changed a favorable report about Palantir to then favor the DCGS.

Odierno ordered an internal Army investigation into what happened. Last week a congressional oversight committee started looking into why the report was manipulated, and has asked the secretary of defense to produce all the relevant documents by August 15.